We are getting calls from our ISP that we have a virus. We have scanned each and every computer using Panda Activescan Pro online and one PC had 15 virus infections but they appeared to be dormant. The ISP cant tell us what computer it is. The only thing I can think of is that it is our server running exchange. We ran Panda on this and it didn't find a virus. Could there possibly be a virus embedded in our exchange? If so, is there a free way to remove and scan? We have a spam filter that is supposed to scan for viruses and spyware before the mail is passed to our server so I doubt something got through but it is possible.