Syyd, it's also possible that the sudden shutdown really didn't have anything to do specifically with Photshop. I've known Windows to do that on occasion even when I'm doing something as simple as typing a message post at R'osity. Sudden black screen, instant reboot, no visible cause. So I'd suggest put the suspicion on Windows, go ahead and open the PSD, poke around the layers, save frequently, and I'll bet you're able to finish the image okay. Good luck! :)