I don't remember the name of the virus but it was extremely annoying because it would give a countdown and after 1min/30seg the computer would shutdown, I didn't had any other access to the internet besides my computer and this made for a frustrating race against the countdown to try to search for a solution and test tools while the virus kept turning off the computer.
I got something very similar too. I never managed to find out what caused it, so I ended up rebooting my computer a few times to back up my files before it shut down, and then I reinstalled windows completely. I haven't had any big problems since then.