Try running task manager (and resource monitor) to see if anything is suddenly hogging CPU. Another free tool is Process Monitor
. It gives a deeper look at what's happening with your machine. You could also try scanning with Malwarebytes Free
. It picks up things that other traditional antivirus suites miss. Update the signatures and run a full scan. If these don't help you could try a System Restore
to a date/time prior to when the issue first began. If no restore points are availabe you could also make sure your temp files aren't overflowing and you clean out your browser cache.