Well, it seems to me that the processor is overheating, or maybe the cooling fan is not working properly or at all, keep an eye on those, try changing the memory to a different bank as well, and by the way, depending on what brand is your computer, in order to access bios you need to press or del, or f2 (hp), or f10 or f12, don't remember quiet well which of the last ones applies to compaq, but the most common key is del....f8 is to access safe mode...and press the key several times as soon as you turn on the machine...let us know