After update to Ubuntu 10.04.1 LTS, system will not boot

First step is to reinstall Grub and see if it solves issue:
   https://help.ubuntu.com/community/Grub2#Reinstalling%20from%20LiveCD
For removing extra kernels have a look at:
   https://answers.launchpad.net/ubuntu/+source/grub2/+questions?field.search_text=Reduce+Grub+menu&field.sort=RELEVANCY&field.sort-empty-marker=1&field.actions.search=Search&field.language=en&field.language-empty-marker=1&field.status=SOLVED&field.status-empty-marker=1

Hi and thanks for the reply. I just got back on my computer for the first time and tried this fix. Here are the results, following the instructions for reinstalling grub from the link you provided:

ubuntu@ubuntu:~$ sudo mount /dev/sda5 /mnt
ubuntu@ubuntu:~$ sudo grub-install --root-directory=/mnt/ /dev/sda
Installation finished. No error reported.
ubuntu@ubuntu:~$ sudo update-grub
/usr/sbin/grub-probe: error: cannot find a device for / (is /dev mounted?).
ubuntu@ubuntu:~$ sudo mount /dev/sda5 /mnt
mount: /dev/sda5 already mounted or /mnt busy
mount: according to mtab, /dev/sda5 is already mounted on /mnt
ubuntu@ubuntu:~$

This was the second attempt. On the first, I went up to right before where I type sudo update-grub, rebooted as per the instructions, and it presented the same blank screen. When I rebooted using the liveCD, I then typed sudo update-grub, and the same grub-probe: error was reported. Then I try to mount sda5 again, demonstrating that is indeed mounted

My ubuntu is on sda5. I don't know why the update isn't working. And maybe the reinstall just didn't work in the first place.

Sorry , if that chronology is confusing, it should read like this:
"This was the second attempt. On the first attempt I did the same as above but rebooted before updating grub. When I rebooted using the liveCD, I then typed sudo update-grub, and the same grub-probe: error was reported as above. Then I begin again as shown above, I try mounting, installing grub, and updating all at once, only to get the same error again. Then I try to mount sda5 again, demonstrating that it is indeed mounted."

 Try again what you did first time.When you see message "Installation finished. No error reported." reboot and remove Live Cd from drive.That should give you grub back.

OK, I tried this again as you describe. After I remove the CD and the computer reboots, it once again goes from the BIOS loading screen to the blank command screen.

If you get a blank screen at boot after install or booting from the Ubuntu install cd please read:

http://www.ubuntugeek.com/how-to-fix-ubuntu-10-04-lts-lucid-blank-screen-at-startup.html

To clarify, I do not get just a blank screen but the same as described above, after loading BIOS:

GNU Grub Version 1.98-1ubuntu8

Minimal BASH-like line editing is supported ..... etc.

So I don't think those solutions would work. I will try them though, and report what happens.

for Solution 1, striking 'e' or 'edit' does not work - it is not a valid command in this screen.

For Solution 2, I had to do this booting from the LiveCD, so I don't know how this would affect my normal boot from HDD. Anyway I tried it, editing the end of the command line using the F6 menu, Ubuntu loaded, and surprisingly the graphics were all changed - different icon types on the desktop (eg, a life preserver instead of a ? icon for help, and a folder instead of a mini desktop icon for show desktop.) No change on reboot to the screen.

For Solution 3, /etc/X11/xorg.conf indeed cannot be found. Maybe this is the issue. However I don't understand step 3, "Copy a new “known good” xorg.conf file to the HD (I had to use sudo cp … otherwise I got permission problems)." Where can I find a new known good xorg.conf file to copy?

Please provide partition table.

If you can't boot from hard drive, boot en Ubuntu CD/USB stik and then choose "Try without install".

Open a terminal: you can either press Ctrl+Alt+T or Applications->Accessories->Terminal.

To copy/paste in a terminal, replace Ctrl+C by Ctrl+Maj+C and Ctrl+V by Ctrl+Maj+V (for historical reason, Ctrl+C is assigned another function).

Paste to terminal one of the following commands:

    sudo fdisk -l

    sudo parted -l

where "-l" is lower case "L".The two commands provide data in a slightly different format.

Copy/paste result into a new thread post.

To run a command as administrator (user "root"), use "sudo <command>".
See "man sudo_root" for details.

ubuntu@ubuntu:~$ sudo fdisk -l

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x0000880c

   Device Boot Start End Blocks Id System
/dev/sda1 * 1 9763 78415510+ 7 HPFS/NTFS
/dev/sda2 9763 19458 77874177 5 Extended
/dev/sda5 9763 19084 74868736 83 Linux
/dev/sda6 19084 19458 3004416 82 Linux swap / Solaris
ubuntu@ubuntu:~$ sudo parted -l
Model: ATA WDC WD1600BEVE-0 (scsi)
Disk /dev/sda: 160GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos

Number Start End Size Type File system Flags
 1 32.3kB 80.3GB 80.3GB primary ntfs boot
 2 80.3GB 160GB 79.7GB extended
 5 80.3GB 157GB 76.7GB logical ext4
 6 157GB 160GB 3077MB logical linux-swap(v1)

Warning: Unable to open /dev/sr0 read-write (Read-only file system). /dev/sr0
has been opened read-only.
Error: /dev/sr0: unrecognised disk label

ubuntu@ubuntu:~$

Now that you mention this, it isnt clear to me which one my ubuntu drive should be - number 2 or number 3

Ubuntu drive is sda2.

Commands to reinstall ( https://help.ubuntu.com/community/Grub2#Reinstalling%20from%20LiveCD ) should be:
   sudo mount /dev/sda2 /mnt
   sudo grub-install --root-directory=/mnt/ /dev/sda

ubuntu@ubuntu:~$ sudo mount /dev/sda2 /mnt
mount: you must specify the filesystem type
ubuntu@ubuntu:~$

Sda 1 and 5 both mount fine, and when these are mounted, the little icons for the two drive partitions disappear from places - this is why I assumed those were the correct drives, not sda2. Any ideas on why sda 2 won't mount?

Sorry, I read too fast last time. sda5 is Ubuntu partition, as you did previous time.

I found this script to analyse Grub configuration: http://sourceforge.net/projects/bootinfoscript/
Could you download it, then run "sudo bash boot_info_script055.sh", and paste result in http://paste.ubuntu.com/, and provide in this thread the link to Web page.

ubuntu@ubuntu:~$ sudo bash ~/Desktop/boot_info_script*.sh
Identifying MBRs...
Computing Partition Table of /dev/sda...
Searching sda1 for information...
Searching sda2 for information...
Searching sda5 for information...
Searching sda6 for information...
Finished. The results are in the file RESULTS.txt located in /home/ubuntu/Desktop
ubuntu@ubuntu:~$

RESULTS.TXT:

                Boot Info Script 0.55 dated February 15th, 2010

============================= Boot Info Summary: ==============================

 => Grub 2 is installed in the MBR of /dev/sda and looks on the same drive in
    partition #5 for /boot/grub.

sda1: _________________________________________________________________________

    File system: ntfs
    Boot sector type: Windows XP
    Boot sector info: No errors found in the Boot Parameter Block.
    Operating System: Windows XP
    Boot files/dirs: /boot.ini /ntldr /NTDETECT.COM

sda2: _________________________________________________________________________

    File system: Extended Partition
    Boot sector type: Unknown
    Boot sector info:

sda5: _________________________________________________________________________

    File system: ext4
    Boot sector type: -
    Boot sector info:
    Operating System: Ubuntu 10.04.1 LTS
    Boot files/dirs: /boot/grub/grub.cfg /etc/fstab /boot/grub/core.img

sda6: _________________________________________________________________________

    File system: swap
    Boot sector type: -
    Boot sector info:

=========================== Drive/Partition Info: =============================

Drive: sda ___________________ _____________________________________________________

Disk /dev/sda: 160.0 GB, 160041885696 bytes
255 heads, 63 sectors/track, 19457 cylinders, total 312581808 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes

Partition Boot Start End Size Id System

/dev/sda1 * 63 156,831,083 156,831,021 7 HPFS/NTFS
/dev/sda2 156,831,742 312,580,095 155,748,354 5 Extended
/dev/sda5 156,831,744 306,569,215 149,737,472 83 Linux
/dev/sda6 306,571,264 312,580,095 6,008,832 82 Linux swap / Solaris

blkid -c /dev/null: ____________________________________________________________

Device UUID TYPE LABEL

/dev/loop0 squashfs
/dev/sda1 3634004834000D95 ntfs
/dev/sda2: PTTYPE="dos"
/dev/sda5 669f801a-3f59-41b0-9735-d3f634b9338a ext4
/dev/sda6 73bc727d-aab0-4097-813a-70960edab332 swap
/dev/sda: PTTYPE="dos"

============================ "mount | grep ^/dev output: ===========================

Device Mount_Point Type Options

aufs / aufs (rw)
/dev/sr0 /cdrom iso9660 (ro,noatime)
/dev/loop0 /rofs squashfs (ro,noatime)

================================ sda1/boot.ini: ================================

[boot loader]

timeout=30

default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS

[operating systems]

multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Home Edition" /noexecute=optin /fastdetect

=========================== sda5/boot/grub/grub.cfg: ===========================

#
# DO NOT EDIT THIS FILE
#
# It is automatically generated by /usr/sbin/grub-mkconfig using templates
# from /etc/grub.d and settings from /etc/default/grub
#

### BEGIN /etc/grub.d/00_header ###
if [ -s $prefix/grubenv ]; then
  load_env
fi
set default="0"
if [ ${prev_saved_entry} ]; then
  set saved_entry=${prev_saved_entry}
  save_env saved_entry
  set prev_saved_entry=
  save_env prev_saved_entry
  set boot_once=true
fi

function savedefault {
  if [ -z ${boot_once} ]; then
    saved_entry=${chosen}
    save_env saved_entry
  fi
}

function recordfail {
  set recordfail=1
  if [ -n ${have_grubenv} ]; then if [ -z ${boot_once} ]; then save_env recordfail; fi; fi
}
insmod ext2
set root='(hd0,5)'
search --no-floppy --fs-uuid --set 669f801a-3f59-41b0-9735-d3f634b9338a
if loadfont /usr/share/grub/unicode.pf2 ; then
  set gfxmode=640x480
  insmod gfxterm
  insmod vbe
  if terminal_output gfxterm ; then true ; else
    # For backward compatibility with versions of terminal.mod that don't
    # understand terminal_output
    terminal gfxterm
  fi
fi
insmod ext2
set root='(hd0,5)'
search --no-floppy --fs-uuid --set 669f801a-3f59-41b0-9735-d3f634b9338a
set locale_dir=($root)/boot/grub/locale
set lang=en
insmod gettext
if [ ${recordfail} = 1 ]; then
  set timeout=-1
else
  set timeout=10
fi
### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/05_debian_theme ###
set menu_color_normal=white/black
set menu_color_highlight=black/light-gray
### END /etc/grub.d/05_debian_theme ###

### BEGIN /etc/grub.d/10_linux ###
menuentry 'Ubuntu, with Linux 2.6.32-25-generic' --class ubuntu --class gnu-linux --class gnu --class os {
 recordfail
 insmod ext2
 set root='(hd0,5)'
 search --no-floppy --fs-uuid --set 669f801a-3f59-41b0-9735-d3f634b9338a
 linux /boot/vmlinuz-2.6.32-25-generic root=UUID=669f801a-3f59-41b0-9735-d3f634b9338a ro quiet splash
 initrd /boot/initrd.img-2.6.32-25-generic
}
menuentry 'Ubuntu, with Linux 2.6.32-25-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
 recordfail
 insmod ext2
 set root='(hd0,5)'
 search --no-floppy --fs-uuid --set 669f801a-3f59-41b0-9735-d3f634b9338a
 echo 'Loading Linux 2.6.32-25-generic ...'
 linux /boot/vmlinuz-2.6.32-25-generic root=UUID=669f801a-3f59-41b0-9735-d3f634b9338a ro single
 echo 'Loading initial ramdisk ...'
 initrd /boot/initrd.img-2.6.32-25-generic
}
menuentry 'Ubuntu, with Linux 2.6.32-24-generic' --class ubuntu --class gnu-linux --class gnu --class os {
 recordfail
 insmod ext2
 set root='(hd0,5)'
 search --no-floppy --fs-uuid --set 669f801a-3f59-41b0-9735-d3f634b9338a
 linux /boot/vmlinuz-2.6.32-24-generic root=UUID=669f801a-3f59-41b0-9735-d3f634b9338a ro quiet splash
 initrd /boot/initrd.img-2.6.32-24-generic
}
menuentry 'Ubuntu, with Linux 2.6.32-24-generic (recovery mode)' --class ubuntu --class gnu-linux --class gnu --class os {
 recordfail
 insmod ext2
 set root='(hd0,5)'
 search --no-floppy --fs-uuid --set 669f801a-3f59-41b0-9735-d3f634b9338a
 echo 'Loading Linux 2.6.32-24-generic ...'
 linux /boot/vmlinuz-2.6.32-24-generic root=UUID=669f801a-3f59-41b0-9735-d3f634b9338a ro single
 echo 'Loading initial ramdisk ...'
 initrd /boot/initrd.img-2.6.32-24-generic
}
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_memtest86+ ###
menuentry "Memory test (memtest86+)" {
 insmod ext2
 set root='(hd0,5)'
 search --no-floppy --fs-uuid --set 669f801a-3f59-41b0-9735-d3f634b9338a
 linux16 /boot/memtest86+.bin
}
menuentry "Memory test (memtest86+, serial console 115200)" {
 insmod ext2
 set root='(hd0,5)'
 search --no-floppy --fs-uuid --set 669f801a-3f59-41b0-9735-d3f634b9338a
 linux16 /boot/memtest86+.bin console=ttyS0,115200n8
}
### END /etc/grub.d/20_memtest86+ ###

### BEGIN /etc/grub.d/30_os-prober ###
menuentry "Microsoft Windows XP Home Edition (on /dev/sda1)" {
 insmod ntfs
 set root='(hd0,1)'
 search --no-floppy --fs-uuid --set 3634004834000d95
 drivemap -s (hd0) ${root}
 chainloader +1
}
### END /etc/grub.d/30_os-prober ###

### BEGIN /etc/grub.d/40_custom ###
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
### END /etc/grub.d/40_custom ###

=============================== sda5/etc/fstab: ===============================

# /etc/fstab: static file system information.
#
# Use 'blkid -o value -s UUID' to print the universally unique identifier
# for a device; this may be used with UUID= as a more robust way to name
# devices that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
proc /proc proc nodev,noexec,nosuid 0 0
# / was on /dev/sda5 during installation
UUID=669f801a-3f59-41b0-9735-d3f634b9338a / ext4 errors=remount-ro 0 1
# swap was on /dev/sda6 during installation
UUID=73bc727d-aab0-4097-813a-70960edab332 none swap sw 0 0

=================== sda5: Location of files loaded by Grub: ===================

 127.6GB: boot/grub/core.img
 137.5GB: boot/grub/grub.cfg
 127.8GB: boot/initrd.img-2.6.32-24-generic
 127.8GB: boot/initrd.img-2.6.32-25-generic
 127.6GB: boot/vmlinuz-2.6.32-24-generic
 127.8GB: boot/vmlinuz-2.6.32-25-generic
 127.8GB: initrd.img
 127.8GB: initrd.img.old
 127.8GB: vmlinuz
 127.6GB: vmlinuz.old
=========================== Unknown MBRs/Boot Sectors/etc =======================

Unknown BootLoader on sda2

00000000 35 4a bf 9a bf 12 b3 7b 5d f8 47 f4 73 51 1d a8 |5J.....{].G.sQ..|
00000010 8d 8e 79 d4 6a 32 36 d3 c2 c6 0a d9 36 8e 15 71 |..y.j26.....6..q|
00000020 98 6f 78 d7 c6 b0 69 40 f9 d2 52 64 bb de bd bc |.ox...i@..Rd....|
00000030 b7 b3 ab ae 76 25 d6 45 e7 4a 72 87 33 6b 17 5c |....v%.E.Jr.3k.\|
00000040 87 cc cc 27 93 31 f8 2d 1d d5 cd b3 41 44 40 89 |...'.1.-....AD@.|
00000050 2e 68 b7 a9 aa ad 8c 2a d8 a5 1f 67 1d 4a ae d6 |.h.....*...g.J..|
00000060 49 88 cd c3 28 ea d6 d6 16 cd 30 aa 9a 65 80 e8 |I...(.....0..e..|
00000070 3a c7 90 35 c4 c0 a4 40 35 05 92 58 1f 1d c0 ab |:..5...@5..X....|
00000080 0f 7c ba e6 99 a9 a9 95 c2 b0 11 1e bd 28 6b 60 |.|...........(k`|
00000090 fe c0 15 57 b3 9f d4 ac dd 75 df b2 99 fc 44 75 |...W.....u....Du|
000000a0 30 d8 e7 5d 3e d4 49 7e 31 8c 14 b0 b6 a2 69 8e |0..]>.I~1.....i.|
000000b0 c3 9b ee f8 d5 1c a9 9c f5 29 39 7b cd 77 7c 3a |.........)9{.w|:|
000000c0 e3 f4 a8 f8 45 59 17 5d 2a 5a db b5 fa d0 5d a0 |....EY.]*Z....].|
000000d0 a1 3d 26 74 b1 bd 7b 43 44 1b 06 4b 9a da a9 ab |.=&t..{CD..K....|
000000e0 df 03 19 a2 ad ce 3a 32 5d ac 93 2a e3 86 a1 d5 |......:2]..*....|
000000f0 ad ae ae 38 71 55 28 cb 01 d0 75 63 c8 1a e2 60 |...8qU(...uc...`|
00000100 52 20 1a 87 26 ff fb b2 40 8b 80 04 a8 68 db eb |R ..&...@....h..|
00000110 0f 43 60 8a 0d 1b 99 65 e8 6d 12 49 a1 6d 2c 3d |.C`....e.m.I.m,=|
00000120 6d a2 35 b3 ed a5 87 a1 b4 c0 f8 e9 81 56 3d e0 |m.5..........V=.|
00000130 ba be 59 a9 95 45 86 5a 95 6d 19 9c c0 4f 13 f7 |..Y..E.Z.m...O..|
00000140 5a 31 0b 7f 98 c0 b0 66 20 b3 fa f0 c3 b2 44 fa |Z1.....f .....D.|
00000150 96 13 01 ac f3 a1 5b d1 85 1a 02 a2 d9 47 9d 2b |......[......G.+|
00000160 69 41 de 69 33 53 ee 98 b6 b9 6d cf f4 fe f9 43 |iA.i3S....m....C|
00000170 d6 8d f7 79 8a 4a 46 4f 9b 38 c7 86 5c cd 55 fe |...y.JFO.8..\.U.|
00000180 56 6b ff f1 61 fc 77 b7 65 fc 5b 07 3c c7 67 90 |Vk..a.w.e.[.<.g.|
00000190 5d 11 d6 6a 7b a8 9b 7a 83 e1 a9 62 75 3c 35 84 |]..j{..z...bu<5.|
000001a0 e5 eb 3c bb d9 4c ad e7 2e 66 bd c5 f7 7d ef 74 |..<..L...f...}.t|
000001b0 b5 7d a9 cb 62 5d 53 fa aa 98 6b f7 0f a6 00 fe |.}..b]S...k.....|
000001c0 ff ff 83 fe ff ff 02 00 00 00 00 d0 ec 08 00 fe |................|
000001d0 ff ff 05 fe ff ff 02 d0 ec 08 00 b8 5b 00 00 00 |............[...|
000001e0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 |................|
000001f0 00 00 00 00 00 00 00 00 00 00 00 00 00 00 55 aa |..............U.|
00000200

Sorry, I didn't see that bit about pasting on the other site.

Here is a link to it pasted to the bin:

http://paste.ubuntu.com/543881/

The script shows no error.
I see currently only two solutions:
   1- asking help to another answerer
   2- installing 10.04.1 from CD/USB stick
I prefer solution (2). If you choose (2) also:

Using a USB key needs a little more work, but it's more easy after to fix issue if they are.
There are many ways to install a version of Ubuntu over a pre-existing one.
a-Do you have data or software configuration to keep ?
b-Do you have an external media able to hold whole "/home" folder ?
c-Do you have more free space on "/" partition that size of "/home" ?
d-Do you want to make a dedicated partition for "/home" (recommended) ?
e-Did you installed lot of software, not installed by default by Ubuntu ?

everyone, thanks for your help on this issue - I ended up just deciding to reinstall completely, and then before updating again downloaded and installed ubuntu 10.10.