how to login ubuntu 8.10 after reboot failed

Maybe try resetting your password?

http://www.psychocats.net/ubuntu/resetpassword

how can i reset my password when it doen`t let me in all i get is login
do i need anything other than my user name and password
is ot opening with the user name and password.

I don't remember user and password what i can do

To discover your user and restore (change) the password you can:

Start the pc the when you see the GRUB row...

Press ESC.

Press "e" for edit.

Highlight the line that begins kernel ………, and press "e"

Go to the very end of the line, add rw init=/bin/bash

press enter, then press "b" to boot your system.

Your system will boot up to a passwordless root shell.

Type in grep -i 1000 /etc/passwd

The system must show a row with your user name at the start of the row
for example:
danilo:x:1000:1000:ubuntu,,,:/home/danilo:/bin/bash

Here my user is danilo

Then to change your user password type in:

passwd username

or

passwd -d username

change username with your real user

Set your password.

Type in:

reboot

or

reboot -f

Hope this helps

Thank mancobra.
I'm still having problems , your sugestion did not work..
I think my problem is my ati radeon hd4670 graphics card,every time i update the driver in ubuntu it crashes after the reboot other than that ubuntu works fine before the card's drivers update even after reboot.
I need the to ugrade the drivers for the graphics card because all the cool stuff you do like compiz do not workwith out it.
andthedrivers are aproved by ubuntu.
mybe im doing something wrong......
any sugesstions.........

If you are still having trouble with this then please post it as a new question. Only the most recent questions tend to get looked at so posting/reposting a question just before america arrives online after work/school gives the best chance of getting a good few answers.
https://answers.launchpad.net/ubuntu/+addquestion

If the problem has been resolved then please follow the link to the forum thread and mark it as Solved.

Good luck and many regards from
Tom :)