So i was downloading windows 10 on my Windows 7 pc but the download failed at second boot. My pc reverted to windows 7. I got a message that says that the download failed at second boot and the my pc has returned to the exact state it was before i started the windows 10 download. Behind the message there's a black screen and i tried to close the message but i can't because my mouse and keyboard dosn't work for some reason. I tried turning of the pc with the power button but then i got a message saying i need to close the message before turning of the pc. But i can't do that because the mouse dosn't work. Now when i press the power button nothing happens. What should i do? I know i can pull out the power cord but maybe that's a bad idea. Please help.