I have used AVG Free antivirus for many years now.  Recently, a new version - V7.0 - replaced the venerable V6.  V7 has new bells and whistles, including auto-update, but the new installation pops up balloons when working, and adds text to the outgoing and incoming email. Fortunately, these annoyances can be turned off.  Here's how.
1 Right-click the AVG icon in your system tray (bottom right corner of taskbar), and launch the AVG Control Center.

Right-click "Email Scanner" in the main pane, and click "Properties". 


In the "Properties" box, click, the "Configure" button and uncheck the two "Certify Mail" boxes.

4 Click the "OK" button.

Next, click the "Properties" button and clear the "Show notification icon" and "Show information window" boxes.


Click "OK" and then OK again. Minimize the AVG Control Centre.

7 You're done!