I have Windows 8 Pro 64 bit and everything worked fine for 2 months, but now suddenly my PC doesn't want to shut down. I've tried restart, but nothing happens. When I log off and try to restart/shut down, nothing happens, just a gray screen shows. I've closed all programs and processes (except some Windows processes that you can't end), I've also updated Windows, but nothing happens.

If I start up my PC and I get the login screen and I press restart, it works (before logging in), but shut down doesn't, it just shows a gray screen. 

There are a lot of posts on this problem for Win7, and a lot of the answers say to hard shut down it (by pressing the power button). I however use a SSD (Crucial M4) and there is an "official" known problem that if you don't properly shut down your pc (eg hard reset), BIOS won't detect the drive. You then need to open the BIOS setup menu and wait for 30min to reset your drive. So I don't want to wait 30min every time I stat-up, so hard shut down is not an option.

I just installed Win8 two months ago, I don't want to format again. Any suggestions on this problem?