The problem seems to be deeper than I initially thought. I re-read your first post and saw that you said the card was not being recognized AT ALL, which worries me. If there was a driver conflict like I was thinking it would have shown up and not worked.
My question is, do the lights on the ACTUAL card come on and everything? I ask because sometimes my card (under ndiswrapper [your card will not work with ndiswrapper]) will blank out, as in, the lights will just turn off and I'll no longer be able to see it in iwconfig and will exprience problems shockingly similar to what your describing. To fix this, I usually unplug the card, plug it into a new port, unmount it, restart the computer and usually the lights will come shining back on and everything will work.
What scares me, is that your card is a PCI card (correct me if im wrong), and so if the card indeed is not being powered, its a much more serious issue.