Win XP freezes or restarts when downloading files

[Scarface523]

I have a P4 1.7 Ghz. Gigabyte GA-8SR533P mobo, 256 PC 2100 DDR, Geforce FX 5200 AGP 128 Mb video, onboard sound, and a linksys wmp11 wireless network adapter. and 20Gb HD. I just bought this computer cheaply for a friend's christmas gift. Installed Win XP, then installed drivers for all components. I have a cable connection, so when I'm online, everything is working fine. But, when I go to download files, windows will either freeze, or just restart. This has been especially happening when I try to download/install SP2, but there are other times when i'm not downloading that the computer will just shut off and restart. I've run AVG anti virus, Macafee stinger, and ms antispyware, and none of them found anything. Also, I've swapped out power supplies, RAM, and HD, but it didn't help. I was thinking the network card may be the problem, but i tested that with another one as well. So I'm thinking its either the mobo or cpu, but I need to know if anyone else has any other ideas that I haven't thought of yet. I really need to get this thing going. Thanks.

 

[pscowboy]

You may have a CPU overheating problem. Often, on comps with some age on them, the heat transfer pad (or the paste) stop doing what they're supposed to do.

If you're comfortable inside the box (be careful about static discharge), see if you can safely remove the heat sink from the cpu. I don't care for the pads, so I carefully remove them, polish up both metal faces, and put a "thin" layer of silver paste on the cpu. When I place the heat sink over this, I twist a little bit to get a good seal; then secure it.

I recommend opening every machine once a year and cleaning out ALL the dust from everywhere, and re-doing the heat sink paste.