I dont know how to go about this problem

[YouRise]

Ok guys I got a huge problem and I think you need a little background information. So may 2012 I bought and assembles my rig which was at the time pretty higj end. About 2k for everything. Have had no problems with it at all until today. Last night I had company and one kid was on my computer trying to download some free games, not illlegally but free and I wasnt ok with it but said nothing. Few actually workes anyway plus I have norton. So normally I boot in about 10 secs with windows being on my ssd, I also have a 1tb and a 1\2 tb drives aswell. This morning it took about 10 minutes and programs, with the exception of google chrome, would not open for about 15 (steam, skype etc) so I fiddled with it turning it off a lot and what. Now once I eventually load windowa and log in the screen is just black. I can move the mouse around, press ctr, alt, dlt and the screen will come up, open task manager etc. But the background is still black. Does anyone have any clue as to what I can do? I had to write this on my phone so I apologize in advance for any errors. Also is this in the right section? Thanks for any replies. This is very frustrating as I've been messing with it for 4 hours and only seemed to have made it worse. I can still open bios btw.

Thanks-derek

 

[Ad Hoc]

Boot into safe mode (with networking) and see if that works. If it does, download, install, and run Malwarebytes and Ccleaner. That should solve the issue. If not, you may have to backup your files and reinstall the OS.

 

[USAFRet]

Go back to an earlier restore point
If you can't get there, maybe a Repair
If that doesn't work, then just a full reinstall.

And for the future, this instance is what guest, or standard user accounts, are for.
They can't install anything without the admin password.