Free hard drive testing programs make this easy. It may be that one of the below solutions is necessary to fix your problem but if you haven't been diligent in your troubleshooting up to this point, you can't know for sure that one of the easier solutions above isn't the right one.
Steps 11 and 12 both involve more difficult and destructive solutions to Windows not starting fully. Make sure you've tried your best to complete the troubleshooting steps up to this one.
