I have a black screen of death problem with my girlfriend's laptop and I just can't get it to work. Could somebody help me with solving the problem? I've ran a bootable hard drive diagnostic and it passed.
Use a System Restore Point to go back to a previous date. I know that there was a post about this on some site about what they found to be the problem. Doing research now to find it. But a Restore Point should get you back up for now.
Sadly there might not be any other option but to format and reinstall Windows. You have tried pretty much exhausted every solution for the KSoD that is out there. If you need to back up the files on the laptop can always use a Linux LiveCD.