Hey there I've been experiencing the strangest thing with my wifi. Basically, while I'm using my computer, wifi will just turn itself off and then I can not turn it back on. If I open up system profiler when this happens, I am told that I have no wifi device installed in my computer. If I restart, it appears as if I have no wifi device whatsoever, as even the menu bar icon disappears. Anyone else had this problem? It's really starting to get annoying. I believe the wifi card might not be seated properly.... but there's no way to tell without a trip to apple