Vague problem description. After searching web, found out it is a netbook. Important piece of info!
So you are getting white screen when turning on the netbook. Do you get the same result if you plug in an external monitor?
At what point you get the white screen? right after turning it on? Or after logging to Windows?
If you see white screen on both monitors right after turning the laptop on, issue is either video card or motherboard. Either case you need to change the motherboard. Cheaper to buy a new netbook, if not under the warranty.