|If it were me, and it has been ME a time or time in your position, I would first uninstall anything that is called Mcafee or Norton. They both suck badly and create more problems than answers.|
Secondly, I would try to go to a FREE online virus scan. Assuming you have hi speed its a good idea. Try Bitdefender as it has a good track record for catching viruses that others cannot. If you look at the trend, both Mcafee and Norton are notorious for NOT seeing viruses.
Stay away from Trend Micro online scan. It takes about a year to get it working. Also avoid Ikarus, they install spyware.
Once you get everything "fixed", I would install Avast Antivirus and keep it updated. It's "almost" perfect. It can get most viruses. But sometimes it misses 1 or 2. So, installing bitdefender or something alongside it will keep you safe.
Its good experience to take an infected file you find on your pc, and upload it to an online file scanner. The reason is because it will scan the file using 40 different virusscan programs and show you the results for each. Thats how you can tell which programs work, and which do not. Mcafee really fails the test badly.
I get a virus once every two years and thats because I am surfing in dangerous waters sometimes. ;)
A last good note that many rookies should know. If you are using a store bought pc that still has factory Windows setup, wipe everything out, install OS fresh and clean from a disc, and eliminate all the factory installed spyware and junkware that is on every store bought pc.