will not boot

Does the system have a make and model?

I have a XFX G Force 8200 Motherboard,AMD Athlon 64 X2 5000+ Processor,Crucial 2048MB PC2-5300 DDR2 667MHz Memory,XFX GeForce 8500 GT Ultra Silent Cooling Video Card - 512MB DDR2, SLI Ready, PCI Express 1.0 x16, (Dual Link) DVI, VGA, HDTV. One 40g Maxtor HD, With Ubuntu 1204 LTS on it. Two other hard drives with XP pro on them. Problem started after installing updates. Don't know if that caused it or not. I run it in recovery mode. Above the BusyBox line the last line says ALERT ! /dev/disk/by-uuid/dd874d17-2c16-401c-8e48-e23f0e572ea3 does not exist. Dropping to a shell!

Try this, hold shift on boot to get to the GRUB screen, and select a recovery mode option (sometimes in "Previous Linux Releases"), and do a filesystem check, and run "clean", and then reboot as normal.

Hope That helps,
Hamish

I run it in recovery mode. When recovery mode is run is that doing the filesystem check?. How do i run clean. When recovery gets done it has BusyBox v1.18.5 (Ubuntu 1:1.18.5-1ubuntu4.1) built-in shell (ash). Enter 'help' for a list of built-in commands. Next is (initramfs) with blinking cursor. If i type in filesystem check or clean it says command not found. I'm running recovery mode for 12.04 LTS

No, you don't appear to be reaching the recovery prompt. A alert message above gives me a hint: Have you moved your HDD to another PC, or swapped IDE/SATA channels on the motherboard?

No have not done any of that. The problem started after an update. I run the update and after it was done i turned the computer off. The next day when i turned computer on i started haveing this problem. Before this problem i had a unsolved problem when i booted computer on i would get the desktop but no dash on left side. I was told to try and run this line in terminal. $ gconftool-2 --recursive-unset /apps/compiz-1;gconftool-2 --recursive-unset /apps/compizconfig-1;unity --reset. I later found by running each line one at a time. The last line,unity --reset, was all i needed to run.

I can not seem to get my problems resolved with the system. Can't use desktop the way it is, been using laptop instead. I would like to know if there is a way to reload Ubuntu 12.04 LTS and not lose what is already there. Or replace with a newer version.

You'd have to copy your data to another system, or a usb stick or similar. You'd lose all your programs and settings, though... Presumably you know how to install ubuntu?

Hamish