I think most integrated wireless on mobos is user replacable, been a while since I had one.
did you add any new components to the computer prior to the problem starting? if not, it is most likely going bad, you can snag a usb wirless dongle(hehe dongle) for less than 20 bucks and they work fine, I use one on my other pc.
http://www.amazon.com/Medialink--150Mbp ... b+wirelessif you have a free pci slot I can probably send you one, if you can't figure it out and don't wanna drop some cash.