At this point, I'd just consider a whole new Windows install.
Do you have the Windows activation key? If so, download the relevant Windows 7 ISO here:
http://www.w7forums.com/threads/official-windows-7-sp1-iso-image-downloads.12325/
...reinstall, and activate with your existing key. Install all your other software.
That's what *I* would do. A lot of times it is easier to just start over, rather than trying to 'fix' something.
Or
From your earlier comment about moving cables around, etc....maybe a physical connection still isn't right.