Virus automaticly logs me off my computer

I had recenty purchased Nortons AV 2009 and the program identified a MH690.A virus with high priority.  There were other lower priority threats.  The CPU usage was very high and it could not remove due to pending status.  I manually turned off the computer, and now when I loggin with password, it automaticly logs me off.  Is there another way to log on or am I froced to reformat? 

 

Edward