Another xp pro random restart issue

I have several computers in our business network that are randomly restarting. These computer have a variety of configurations - some are EMachines (purchased before I took over) and some are Dells. The Dells have ATI video cards, the EMachines have NVIdia video cards. They all have ATI TV Wonder 200 video capture cards. They have power supplies around 300W - 305W. The random restarts seem to be a problem especially when trying to do video recording. I've been thinking it is everything from the video capture card to overheating to configuration errors. The Microsoft Help suggests it is an unstable driver. Since all the computers are saying this, I'm thinking maybe the video capture card, the ATI TV Wonder 200. Still, I would love some help on this. I will include a few minidump logs for one afflicted computer. This is an EMachine with an NVidia card. I know I could be dealing with different issues in each computer, but maybe a common link? This EMachine is about a year old.

oh, and another thing - I would really like to know how to read these Minidumps. I have found information from microsoft on displaying the text. Where is dumpchk.exe? I could have sworn I've looked at these files before and dumpchk was already on the computer. Anyway, I tried installing the debugging tools from Microsoft, but I don't see dumpchk in there. Any thoughts? Then of course, when I get that far again, I could really use some suggestions on where to learn how to interpret these files. Thanks again - really appreaciated.

okay, found the dumpcheck utility, had to put it into my root drive, then change my directory to the Minidump directory before I could view the file. I noticed there was a sympath switch. Is that used to identify the path to the minidump file when dumpchk is in a different directory? Look forward to understanding this gray area.

Four of the dumps are exactly the same, which can indicate a software problem. The process in all five is either WebCam.exe or CatalystMC.exe. I would try updating the video capture card's drivers.

Minidump Tutorial: http://forums.majorgeeks.com/showthread.php?t=35246

thank you so much for your timely response. I have looked into that in the meantime and found an update. I will try that and see where it leaves me. In the meantime, how can I learn how to interpret these minidumps? Is there an online resource that demystifies the issue?

duh, didn't notice the link - my fault. Thank you again