Top 5 to do when you upgrade to Ubuntu Linux 10.10 and your computer won't start

Here is top 5 to do list when you upgrade to Ubuntu Linux 10.10 and your computer won't start

Okay, first thing first, most likely you'll need to wipe everything and install Ubuntu again but as mentioned previously, I hope you have a backup for everything.

2nd step is: Boot from Ubuntu LiveCD and DO NOT install, just choose "try without installation".

3rd step: while you're on the live session, try to use GParted to format the root (/) partition and format the swap partition too.
If you have /home partition then keep it, DO NOT format it.

4th step: Try to install Ubuntu again. Try 8.10 or 10.10. I'd recommend to try 8.10 as 10.10 has lots of issues lately.

If nothing changed then ...

5th step: boot into the liveCD, choose "try ubuntu without installation" and use GParted to wipe everything. Remember, you need a backup for your important files before anything.

Source : http://ubuntuforums.org/showthread.php?s=2076883a093347c5b16f9ad6c194d78d&t=1600910