Odd, possibly a virus

When I'm on the net, my browser will freeze up.  I can't go forward or backward, nor open websites.  But the computer isn't totally locked.  I can minimize, and bring up my Norton.  This opens the Norton Internet Security window.  When I click "scan now" to run a scan, the "Computer Scan" window opens and closes very quickly, just a flicker.  And so, I can't scan.  If I turn my computer off and back on, which I have do from the switch, the normal shut-down method not being functional, it usually restores things.  I have had to do system restore to get things to run, too.  Just today, that didn't work, either.  I couldn't get the system restore window to work.  But just turning it off and on seemed to do the trick.

 

I'm assuming it's a virus, though I don't know for sure.  Any suggestions on solutions that won't run me several hundred dollars?