My computer keeps locking up

[JPodL]

I just built a computer and it's been locking up. Here's a list of my parts:
Gigabyte GA-7VRXP w/Athlon XP 1800
PC2700 512mb ram
WD 80 GB WD800JB
Lite On 32X12X40 CDRW
Toshiba DVD (SDM1612)
Aopen GF4Ti4200 (128mg)
Teac 1.44MB Floppy
SB Audigy 5.1
Windows XP

I've gotten everything working, excpet that my computer frequently locks up. This is especially true when I try to play a DVD. I have gotten the dvd to just start so I'm pretty sure it's all right, but it's always locked up. It will also lock up if I just leave the computer on for awhile. I'm not sure what the problem is, but any help is appreciated. Oh, I'm using WinDVD and the hard drive is the master on the primary ide. The CDRW is the master of the second ide and the DVD is the slave of the second ide. Thanks.

 

[iamwiz82]

first off, run the PC with just minimum to keep it up. Do you have extra RAM? Use some RAM that is not in the system now and one by one add peripherals to it until it starts freezing. You will then know what is having the problem.

You may want to go into the BIOS and watch the temp. of your CPU. It could be overheating and crashing. Did you use thermal paste on the heatsink?

 

[JPodL]

Thanks,
ok I think it might be the video card. I haven't been able to get the dvd player to work yet, but I could get a game to work. (Age of Empires II, not taxing on the system but I like it.) After I installed all of the drivers and associated programs on the video card cd the game wouldn't work any more. Is there any way to be sure other than getting a whole new video card?