yes, sounds like the cpu is overheating
options,
turn off, at wall socket but leave plugged in h88p://www.fonerbooks.com/replace.htm for reasons for leaving plugged in but turned off, static risk if no any static protection is handy
open case and see if either fan is blocked or clogged etc, not free spinning
if you have a vacuum that can blow air use that, if not you need to clean the fans, can of air is great for this, but not everyone owns or carry a can, i'm a sad one that's always has one handy tbh
http://www.overclockers.co.uk/showproduct.php?prodid=KB-010-OP&groupid=702&catid=1568
if you can replace, if not a really good clean, if it still doesn't work afterwards, then reseat memory, unplug and plug back in (just to try if it's memory) or replace cmos battery (they don't last forever) go into bios and see if time has been kept etc, a shore sign of faulty settings is wrong date and time
retry test.
still nothing, you may have other hardware problems, over cooked your cpu etc, or faulty hardware elsewhere