I don't know of any easy way to determine what is causing the BSOD because you can't boot into Windows 7 to run any programs like WhoCrashed or BlueScreenViewer.

See if there are any mini-dump files in C:\Windows\Minidump. If yes copy them to a flash drive, then zip and upload here so we can look at them. See here for instructions: Copy & Paste - in Windows Recovery Console