How computer literate are you?

I suggest making a back up of all the important things to you. When reformatting, I suggest partioning the drive so that the C:\ drive is just for windows and say D:\ is for other things. That way, when it comes to reformatting again or there's a problem with windows, you won't have to touch other important stuff.

Make sure you have all the drivers for your hardware, passwords etc if you're on a wireless setup......