Freeze on boot up

[#1]

Anybody came across any issues where Ubuntu 10.04 freezes on boot up? I get them every now and again, it goes through the bios boot up then sticks at a blank screen with just a cursor flashing away in the top left corner. Usually at this point I get a green screen and ubuntu kicks in. I have to reboot a couple of times to get past it.
It seems to be just before my graphic card kicks in, I can tell that it's going to start because I hear the fans slow down on the video card.

[#2]

I get it maybe once every couple of months - whilst I have a separate video card, it doesn't have any fans on it.
I blame some BIOS malfunction (occurs on last few Ubuntu versions).
Only appears on one PC that I'm aware of.
BTW Still using GRUB Legacy.
CTRL+ALT+DELETE fixes it. 

[#3]

Quote

CTRL+ALT+DELETE fixes it

What do you mean?

[#4]

It causes the PC to re-boot - and because this is such a rare occurrence, everything works.
I suppose it's really a workround - but Linux hasn't had chance to log anything so the chances of a proper fix look slim.

[#5]

Must be a bad Linux week, my 9.10 Karmic at work has had a fit aswell.  Took for ever to boot up then the keyboard and mouse stopped working after updating to a newer kernel. The new Kernel won't boot and when I switch back to the older one mouse stops working. I'll try a different keyboard and mouse tomorrow.