Try booting into safe mode without network and see if you can run System Restore from there to revert your drive back before the problem. If that won't work, on another computer make a bootable USB with anti-malware, and antivirus on it. Boot from there and scan your HDD. You may need to set your BIOS BOOT sequence to allow this. If you get that done then I would uninstall and reinstall, or switch to another browser until you getthe computer cleaned out.