Windows 8 black screen

Hi, for some reason whenever I turn on my PC the lock screen appears and if can type the password but when it unlocks everything is just black, I can't see anything nor open anything, obviously it's windows 8 and this was not a problem for me before, I can open task manager but I can't do anything else, I took the battery out and took everything off (USB, mouse, etc) but it still doesn't work please help.

Explorer.exe crashing would cause that. The other would be that you accidentally hit the Function key to use a connected monitor in place of the onboard Graphics GPU.. How long have you had this computer?