I have an Acer 5542 Gemstone laptop computer that comes pre-installed with Windows 7. I haven't used it's Wi-Fi capabilities for quite a while but now when I try switching it on, the Wi-Fi LED won't light up. bluetooth works fine though.
But when I boot into Ubuntu, the LED starts to glow and Wi-Fi starts working again.
I'm not sure, but I think I might have removed something from the 'Run' registry items.