After following Essexboy and you’re clean, you can change the Heuristic settings of the Mail scanner to identical messages.
Open Internet Mail provider settings and see the two Heuristic tab of settings.
Also, it will be good if you download, install, update and run AVG Antispyware. Some users recommend SUPERantispyware, Spyware Terminator and/or a-squared (take care about false positives).
If any infection is detected, better and safer is send the file to Quarantine than to simple delete than.