Can you boot in safe mode? Safe mode with networking?
If you have a virus, malwarebytes just might find it in safe mode.
http://www.malwarebytes.org/That is a not for progit web site and the do the best job I know of.
The program is free and they do not try to get you to buy
something you don't need.
If you have a USB stick, try and save your important work. Like Photos, musid or projects. You may have to do a re-install even after using malwarebytes program.