If it hangs on loading windows, then try unplugging things like mouses, usb, etc..
Also run this : SFC /SCANNOW Command - System File Checker
Probably wont fix this problem, but it's a good task to carry on with. Run it 3-4 times with reboots in between if it is finding and fixing errors. It may even fix it miraculously.
IF troubles still exist this would probably be the fastest and most reliable fix: Repair Install