We have noticed several users receiving undeliverable messages in their Inbox. Unfortunately, they did not send out these emails and considering that they are receiving quite a bit of these messages, it has led me to the conclusion we have been hit and infected with a bot. We are running Exchange 03 and PCs with XP SP2/SP3. Our Symantec and Trend Micro were not able to find and remove. Anyone have a method they have tried successfully to find and remove a bot from a network. Thanks in advance for the help.