Following on from Kat's message, it would definitely be worth trying a known working monitor and keyboard (speak to your IT person at school if you don't have access to one).
But then if that doesn't work, you should perhaps seriously thing about cutting your losses and wiping the hard disk and re-imaging the system. It always hurts to give up on a problem but then one of the posts suggests that although you seemed to have cleaned it temporarily, it all came back. You reach a point when you are spending more time trying to clear up a mess, when it would be quicker to start over.
Hard decision, your call.
Help, my PC with Windows 10 won't shut down properly
Since upgrading to Windows 10 my computer won't shut down properly. I use the menu button shutdown and the screen goes blank, but the system does not fully shut down. The only way to get it to shut down is to hold the physical power button down till it shuts down. Any suggestions?