This is one of my main gripes with moving to Mac. I spent 10 years owning a Mac only and it has left me kind of behind in the Windows world. I left just as XP was released so anything prior to that I am extremely well versed in.
Ive dabbled with XP but to no real extent - my boys have XP laptops - and Vista/7 I have merely played with.
Sticking with one OS has left me out in the cold with others. So moving from Mac a my main OS is what I am doing. I still have an old Mac - which my wife is using - and I am about to dedicate my time to Linux.
However I will be dual booting with either XP or 7 to keep my hand in.
Helping others has always been a passion of mine. Computing knowledge is a gift, you can try and learn but if you dont have that natural nerd in you it is a struggling battle. I am like a techno-sponge and I bestow what I can on others.