Still cant work out why the wifi card keeps greying out, it works fine in ubuntu so is certainly not a HW problem.
I've had network driver related problems ever since Vista existed - while XP runs fine as always. It's either the drivers or Vista, it's too hard to tell where the fault is exactly. With the number of driver updates I've been through, I'm guessing a this stage it's Vista.
There is an update that isn't available through Microsoft update yet that may or may not help. I installed it yesterday and noticed no negative side effects ;] But this was recommended to me through Problem Reports and Solutions and is related somewhat to network issues, so maybe give it a shot:
http://support.microsoft.com/kb/941649