I had this issue, so I do know how frustrating it can be. Firstly, remember to access the F-keys on a MBP you need to hold down the Fn key (bottom left, next to ctrl). Then make sure F8 is not set as a hot key for Spaces, Expose or similar.
Now you should be good to go
BTW it may be easier to reinstall Windows now ... or at least that's what I had to do!!!!! :smileyhappy: