|You are not getting F8 to work. It may be an issue with some usb keyboards. |
In any case I suspect one of two issues. One is a virus and the other is some file damage.
Might be possible to use a restore point if you borrow a ps/2 keyboard and get to safe mode. If that even works. At least you could try to access the event logs. They should tell why it is rebooting. May be a service that is failing that you can set in services to simply ignore instead of reboot.
Why did it take me over a year to phone in a problem to ATT?