Laptop dead

I have an Acer laptop that has Windows 7 home and Ubuntu on it. It normally boots to the Ubunt options menu from which I select Windows 7. (I haven't got around to doing anything with Ubuntu yet)

Turned it on today and it tries to boot. It gets as far as the initial ACER screen, and the "Press F2 to enter setup" and "Press F12 to change boot device " messages at the bottom of the screen, then shuts down, and repeats. Over and over again. It doesn't respond to F2 or F12, and a repair disk in the DVD drive doesn't have time to do anything. I can hear the drive reading the disk, but it shuts down and repeats before it can read the disk.

Any thoughts?

Oh, and I can't turn it off. It won't stop repeating. I'm going to have to remove the battery to stop it, I think.

Thanks,

 

Update: When I closed the lid to remove the battery, I noticed it didn't shut down. So I opened the lid. I was too late for the Ubuntu/Windows boot menu, and it booted into Ubuntu. Then I got a message I have never seen before, to the effect that my graphics were not good and would I like to use a basic graphic interface. Or words to that effect. I only saw it once. It seemed to stall when I said okay, with a blank screen for a few minutes, so I rebooted with the on/off switch and it's back to the events in post # 1. Even closing the lid I haven't been able to reproduce the event described here.

I shut it down by removing the battery. I checked the RAM and HD connections, all good.