I've got an office with a virus sending out Spam through our Exchange server. The Queue shows thousands of messages. The Trend Antivirus we have on the server and PC's seems unable to isolate this problem or even tell me the PC that is the source of the problem. I have run Trend and Malwarebyets scans on every station and the server. I have checked and its not an 'open relay' How can I find the source of the problem and remove the virus.