Changethe wireless card? I did this on mine recently to go from N to G. It's usually pretty easy: Unscrew the cover to the wireless card, unclip the 2 (or 3) aerials, unscrew the screw holding the wireless card in place, swap, reverse.
Yeah I know I should I just couldn't be bothered
I agree if Windows is taking more than 20 mins to install something is wrong
I have a 64 bit version that also installs a lot more and that still only takes about half an hour