I fear i might have a virus on my windows 8 computer?

[ressp12]

My computer came stock with Norton, but a month after purchase when i try to scan, nothing happens. I press full scan, but nothing. i then tried looking through task manager for any suspicious looking applications, but found nothing. I haven't entered any suspicious websites (I'm mainly using steam, facebook and youtube). i tried using system restore, but still nothing, i click the button to select restore point, and nothing happens. Is there anything i can do to resolve this problem?
I have 16Gb RAM and the most memory intensive program i use is Firefox, but even then i minimise the amount of programs i run. But i don't believe it is a speed issue, as i've been using the computer 3 hours since the problem began (Even a game with no performance issues at one point). is there any way to force a virus scan as it seems my notebook refuses to do anything that would fix a virus problem.
Also, the antivirus isn't finding nothing, it's just not beginning the scan to begin with.