I was registering for college classes this evening when my computer sudddenly closed all open programs and restarted itself. It wasn't a crash restart, but an operational shut down and reboot. It was as if someone hit the restart button. And when it rebooted, it got stuck at the "loading operating system" screen forever.
I've taken the boot drive out and checked it for functionality on a dock connected to a different computer, it appears to be fine and fully operational, with all files intact, and I'm running a virus scan on it as this is written.
I've tried booting the system without the drive and it detected the missing drive and gave an error message. So I know the system can tell if the drive is gone. And then I switched the SATA cable, plugged in the power, yet it got stuck at the same screen once again.
The PSU is a Rosewill RX850, around 2 years old. I've never had any problems with it, and both my SSD and my storage drive are still showing up in the BIOS. I'm probably going to do a repair installation or complete reinstall of the OS. I think the problem is software related. I just don't know for sure.