Comment 10 for bug 577671

If you needed noapic to install time like me, then you need it again to run.

When the boot choice screen comes up, there is an explanation at the bottom, I think you just have to hit the e key and then you can edit the boot options. Easier just to try it than for me to explain.

Further to my postings above, I find that at the boot choice screen if you choose the second line which is recovery, then you can then choose to run with "failsafe graphics" - an error message comes up, but continue and then the system will run stable, with no need for the noapic option.

So those are two workarounds to this problem. I hope it helps somebody debug it. There is a considerable discussion going on in the Ubuntu forum Ubuntu 10.04 (Lucid Lynx) Random Freeze / Hang-up of other with similar problems.
Anthony