most issues i've had with computers have been sound-related
make sure the card you're using is compatible with your OS - it seems obvious, but this has happened to me before where a new MB with built-in sound didn't like win98se. it liked 2k, and 98 first release, but not 98se and when i checked the driver details, it turned out that 98se wasn't listed as being supported...how random is that!!!?
also the BIOS sounds highly suspect - ESPECIALLY if your MB just came out.
IB TWS has some issues with LINKSYS NIC's...i've used a d-link NIC card for over a year before switching to a MB with integrated NIC and haven't had any issues with either one...
btw, CRUCIAL's memory is top-notch. mushkin is good, too, although i got two bad sticks from them once, but their customer service was OUTSTANDING and they overnighted me a replacement no extra charge. i've only bought from each vendor twice, but both are highly regarded.
btw2, matrox tech support is outstanding. before you pull the video cards, be sure to post to a forum there about the problem you're having. usually they will know off-the-bat if it's a common problem caused by the g200...