|Getting into the bios won't be F8. That's to access the boot menu. Bios access is usually F1, F2, DEL or F10 for compaq. If you can't get into bios setup then it must be a hardware issue and not windows. So you might want to verify if you can get into bios setup.|
What is the exact wording of the warning? It asks if you want to continue. That implies a keystroke or mouse click. Are you able to do that or is it locked out at that point?
Are you sure the mouse and keyboard are plugged into the correct ports? Have you tried a different mouse and keyboard (other than the USB ones)?
Did you make any changes or did anything happen to the system between the last time it worked OK and the first time it didn't?