I successfully installed the newest NVIDIA drivers (275.33) in Windows 7 64-bit and rebooted afterwards just in case. After the reboot, I got an error about missing MBR. I disconnected the slave disk so that Windows doesn't get confused and got this message:
DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER
It seems that Windows doesn't recognize the main disk anymore. I booted from Windows install disk but the main disk doesn't get listed as possible Windows locations to repair, and I can't get to it from the recovery prompt.
The BIOS does recognize it, and I'm able to see it if I run
diskpart - however "detail disk" in diskpart says that there are no volumes on the disk. I also tried
bootrec /FixMbr without effect, and
bootrec /FixBoot which gives the error message:
Element not found.
What else can I do? Why would diskpart say there are no volumes on the disk?