my computer freezes every 30-45 minutes, but it doesnt freeze when u boot up and stay at the log in screen. one of my case fans isnt working anymore and i had the PSU for almost 4 years. its a thermaltake silent purepower. the cpu is almost 3 years old (intel p4 3.0ghz 800fsb). Im not sure if its the PSU, maybe cpu, or maybe a virus which i doubt it would be, but you never know.

Classic symptom of heat problem. Open the side of the case and make sure system is clean of heat trapping dust. Blast a desk fan in there and see if it still freezes.

Case fans are cheap - you can buy 20 or so for the cost of new CPU. If your case supports 120mm fans, use them - they move massive amounts of air but at a much lower RPM, meaning they are much quieter too.

it still freezes. everything is at a cool temperature. The CPU temp was at 40degrees celcius after running about 45 minutes.

Well then that points to any number of things, including the PSU as you suggested. However, for it to consistently fail after about 45 minutes is rather odd. Have you scanned for malware?

You might also test your RAM. To test your RAM, I recommend MemTest86+. Select Download - Pre-Compiled package for Floppy (DOS - Win). Unzip the file to a convenient location, insert a formatted floppy disk in the floppy drive, double-click on install.bat to install. Then, with the floppy in the drive, reboot the computer. The computer should boot to the floppy and start testing your RAM. Let it run for several passes or even overnight. You should have no reported errors. Instructions to create a bootable CD version is available too. An excellent how-to guide is available here.

You should also inspect the motherboard for leaky capacitors. Leaky capacitors are a common cause of sudden system lock ups and reboots. Look for white to dark brown dried foam leaking from the tops or bottoms of the capacitors. The capacitors look like tall soda cans, many of which surround the CPU socket. Bulging capacitors are a sign leakage is about to occur. A motherboard with leaky capacitors can be repaired, but generally it is more cost effective to replace the motherboard.

i did a memory test (memtest86) but it stops at the end of stage 2 or begining of stage 3. I left it running for 30 minutes and it didnt move. it hasnt frozen because i can see a cursor flashin under something, but my keyboard doesnt work while the test is on; the lights flash on then go off. I'll check the mobo out soon.

You may have to test with one stick at a time.

every stick still brings a freeze in 30 minutes. dont see any leaks or burnt spots anywhere on the mobo. guess ill try another PSU

Any luck?

ive tried new memory and still freezes. im waiting to find/get a PSU with a sata power cable my hdd doesnt have a 4 pin connector. my programs dont load up properly sometimes now in the task menu when booting up.

Adapter