Computer keeps freezing!!! HELP

Recently, my 3 year old 1.1ghz PC began freezing randomly. I do not know what can cause this. I know for sure that it cannot be a software problem because I have reformatted it with the same problem. The computer would randomly freeze out of no where. Sometimes it would go good for several days, but at other times, it will freeze multiple times in a short time. My guess is that it might be the power supply, but im not sure. It is a 250W power supply. The specs on the comp are as follows: 1.1ghz athalon, 128mb ram, 80gb 7200 hdd, 2 cdrom drives. My second guess is that it might be the hard drive. Any help? THanks a LOT.

.DaVe.

My first guess would be a dead fan - make sure all your fans are up and running like they should be.

It could be the PSU wearing out, thats an alright guess too.

Have you checked the voltage readings with any monitoring software? (Motherboard Monitor 5)

If its related to CPU load, then it is a cooling problem. CPU load increases, freezes more often = cooling problem.

By freezing you mean the screen locks up and the system becomes non-responsive, correct? You don't get any restarts or anything?

Check the HDD for errors: Press windows+r and type cmd then hit enter. Type chkdsk /f then hit enter. It will ask you if you want to scan upon next bootup, type y and hit enter.

my fans are all running, i checked that. And yes, when I say freezing, i mean everythign locks up, noway of getting out of it unless you manually shut it off from power button. I havent checked voltage readings, i might look into that. im also pretty sure its not a cooling issue. A friend just told me he had a similar problem, and it was his memory, he replaced his sticks, and his comp was working again, could this be a factor? thanks.

Did you run check disk? Do that to eliminate the HDD as a factor.

Run a memory test - prime95 would do the trick - and see if it gives you errors. If you get no errors the problem isn't your ram, if you get errors, then set the timings looser and see if that helps.

Have you ever cleaned the inside of the computer? Check the heatsink for dust, just because the fans are spinning, doesn't mean that the temps are ok. Dust build up can cause overheating!

My first guess would be a heat issue. However, you should check for a Virus.

You could be chasing your tail trying to find that one. Something is definitely failing. Sounds like either the Power supply, CPU or even maybe a failing memory stick

i cleaned the inside w/ compressed air, its all clean, not a spec of dust. It cant be a virus, because I reformatted, cleaned out the HD. This leaves it to be a hardware problem. I think its either the RAM or the PSU. Ill check discs, mem and voltage..see if that helps. Any other suggestions are welcome, and thanks for every1 that has helped already.

What are your temperatures at full load? Download Prime95, whip out something that'll record your temperatures like Motherboard Monitor and run the torture test and see how high you're hitting.

Although you say randomly, are you running an intensive program or do you just wake up one morning to see that it is frozen?

I would just recommend reseating that heatsink. After 3 years, the thermal paste probably isn't effective anymore and what not. I would download a hard drive diagnostic program from the manufacture and run it and see if there is any problems with your hard drive. I know when I had a bad HDD, it would lock up hard.

Swap video cards and see if that works too.

I think your problem lies there.. video card, hdd or heat.