I know what you are going through. Like I said earlier.. I went through the same thing.. Do a fresh install make sure you format the drive in which Windows is on and make sure you don't install any of the drivers let windows do it. Also don't try to dual boot it won't work..Realtek is having...
I've had this issue so many times. Realtek has these problems with vista as well...just don't update any of the drivers..do a fresh install and don't install any drivers and don't update till Realtek fixes this issue.
So I have Windows 7 Ult build 7068 and I can't seem to remove the watermark.. I've tried to search the forums but no luck...any help would be great! Thanks