Could be an issue with the card itself, I dunno but removing the card should've stopped it altogether if the system was overloaded on IRQ's. Believe it or not I've actually done that and have had to start removing things in order to use another piece of hardware.
Phenom II 940 Black Edition quad core @ 3.5Ghz
2x1 gig OCZ PC26400 Platinum, 2x1gig GSkill PC26400
Some other stuff,
Even more stuff,
If the automobile had followed the same development cycle as the computer, a Rolls-Royce would today cost $100, get a million miles per gallon, and explode once a year, killing everyone inside. --Robert X. Cringely, InfoWorld magazine