Ok, thanks for the replies guys.
Tom: The riser card is seated in the case such that it can't be moved unless the motherboard is taken out (the mobo plugs into the riser card, not the other way round). There doesn't appear to be any components on it that would fry easily (ie chips, IC"s). I guess the controller for it could be stuffed though.
capybara: There is no option like that. It gave me an idea though, so I turned PnP OS off. Red Hat detected the USB controller (which it didn't before), but it doesn't start X now, even when I switched back
I just tried flashing the BIOS. Hmm, I'm not sure that it did anything, it went so quick (about 3 secs). It also made some really scary beeps. Luckily, it booted properly, but nothing changed...
BTW, I know that the LAN cards are getting power because the LEDs on them turn on.
Any other ideas???