Hi, i have a major problem with my PC, every now and again, probably 5 times a day, more if i'm on 3d games, my computer will either lock up, or completely reboot.
This is starting to do my head in and was hoping for some help.

Originally i thought it was maybe my graphics card (Sparkle Geforce 2 MX 100/200) but after changing it with my other one (Sparkle Geforce 2 MX 200) is still does it, if not as much.
Now i have to be honest and say that a while back my PSU blew and so i needed to replace alot of my parts. However, i did keep the original agp card, original hd and original ram. COuld one of these be at fault?

My Spec is:
AMD Athlon XP 2000 (266mhz)
Gigabyte GA7VR VIA KT-333 socket A
512MB RAM (branded)
40gig IBM HD
Sparkle Geforce2 MX 200
400W PSU

I'm also running Windows XP

Well, i would say its your Graphics card, everything else looks pretty good. Try running some of those games in win98 compatbity mode. To see if that helps. More than likely its your Graphics Card. Run 3dmark2001se and have it test it. If your system restarts then its Your Graphics

Thanks for replying, i've tried the 3dmark2002 and it crashed once, but then i updated the monitor drivers and it worked fine, but i have no idea what the results mean for my graphics card.
Here are some of the basic details, hope someone can help tell me if this could be the cause of all my problems:

Total 3d points: 2278

Game 1 Car Chase - Low Detail 37.9 FPS
Game 1 Car Chase - High Detail 20.7 FPS
Game 2 Dragothic - Low Detail 33.3 FPS
Game 2 Dragothic - High Detail 13.9 FPS
Game 3 Lobby - Low Detail 41.4 FPS
Game 3 Lobby - High Detail 23.1 FPS

Probably a cooling problem, I had the same problem with my 2100+ and I bought a PowerCooler Double Blade Fan and now its working great even if I overclock it

you may have a technical fault with your harddrive as when my PSU failed it knackered my drive so that it kept pausing every 2 or 3 minutes which causes the PC to reboot because it thinks the HD has become detached. Go to your harddrive manufacturers website and download a DOS diagnostic programme for your harddrive and it will tell you if there is even the slightest problem.

Thanks for the help, but i've checked the HDD with the IBM software as i've done before, and it came back 0x00 which basically means no faults found, even on a massive full advanced check.

Also, i very much it could be a CPU cooling problem, only because the cpu came with a genuine AMD cooling fan, and its running steady at 6000rpm and a temp of between 50 & 60 degreesC

Anymore suggestions? Could it be the RAM? Or is my graphics card just too old for up to date games?