Mac, here is a link to a piece of software we use on our servers as well as our client's server with very good results. This software (spywareblaster) catches the code before it gets to system. Is it absolutely perfect? No, I don't think so but I can tell you that we have had very good success with it. You may need to use this in combination with something like Grisoft's AVG/Anti-malware. But I would take it one step at a time. If you need help email me and I or one of my techs can log on to you and lend a hand. Hope this helps!
I have already left a no charge message with the support department in case you need to contact:
http://goparagon.com or
http://paradoorusa.com
http://www.javacoolsoftware.com/
SPYWAREBLASTER.EXE is the one you want to download