Suspicious scanning of computer by Norton 2010 Internet Security

Hi,

 

     I have something wrong with my computer.  Norton Internet Security keeps scanning my computer and tells me I have unresolved threats but it doesn't identify any virus.  I have ran Antivirus in safe mode and got 57 threats wit h Advanced Heuristic Protection set to Aggressive.  It does the same thing in Normal mode but does not list any particular viruses that it has found, just that I have 57 ?  What is the cause of this, is it an actual virus I have on my machine or is it something that needs to be patched ?