Help! My Comp Just Turns Off For No Reason!

I have no idea why, but I'll be using my comp for the past few days and all of a sudden it just shuts off, no warning or anything, but everything else in the surge protector stays on, moniter, speakers, usb hub. And then I can't turn it right back on by pressing the button in front, nothing happens. First I have to turn the main switch on the back, then undo the power cord off the back, then plug back in and flip switch on. After all that, I hit the button in front and it justs blips on for a split second and goes right back off, with nothing happening again unless I do the unplug process all over, and this just keeps happening and happening for like 5-10 times before it finally works and turns on, but then it onll stays on for maybe 5 minutes before cuts off again, no warning. What is going on here? Can my power supply finally be going as the comp is about 5 years old? It can't be a virus as I've run 5 different virus scans from zonealarm,mcafee, norton, AVG, and avast along with spyware runs from spybot, zonealarm, avg, ad-aware, and nothing is being found other than the normal tracking cookies, which I deleted both thru the programs and clearing IE cookies and such. Please someone help me out as I really need this comp to run right as its also my work computer. Please send any replies both on here and at the same name @ aol. Thanks for your time in reading all of this, have a good one

 

forgot, I'm on win XP pro that I just had to reinstall for some unknown reason, just turned it on one day and was all screwed up, oh well had a backup disk all went fine, but when I let it do updates, its now trying to say that my xp pro isn't authentic, but I have athe real disk that I bought 2-3 years ago and calling microsoft is of no help. could this in anyway be making it cut off on its own?

 

Sounds to me like a thermal problem; the PC is probably overheating. Unplug from the power cord to the wall (it'll probably be easier to unplug everything) and pull the side off the tower (you'll need a phillips screwdriver) and take a look inside. If you see lots of dust, debris, and assorted crud, then temps are the culprit. Go to the nearest PC store and grab some canned air, take the tower outside, and blow all the dust out from all fans, chips, heatsinks, etc. Be careful with the canned air; use short blasts. If the can starts to get cold (and it will), stop before it gets frosty or else liquid will start shooting out into your PC and that's not good. Also, check all your fans (CPU, video card, case fans, etc) and make sure that they're totally clean and that they're spinning freely without ANY friction. If they don't spin nice and easy, you'll need to replace 'em..... let us know what happens....

hd2k

BTW- All of the above goes for the power supply also: blow the crud out, and check the fan(s).... whilst in the PC, it wouldn't hurt to reseat all your cards, memory sticks, drive data and power cables, etc....