Problem threat that continually reappears

For the past couple of days, I have been having issues with a particular threat that appears in this directory:  c:\windows\system32\ and ALWAYS appears as a different .exe file within this directory.  Norton removes the threat but I have NEVER had this sort of thing appear repeatedly as a threat or otherwise.  I have NO idea how I picked this thing up but it keeps coming back and Norton continually deletes it but I want it gone altogether.  Any ideas of how to get rid of this thing?  Attached is a screenshot of what Norton has done and you can see how often it keeps popping up...thanks in advance...