When Windows Vista finds new hardware has been added to a system or a new device has been detected, a popup balloon appears to notify you, even if no other response is required from the system's user. You can disable this annoying popup by editing Local Group Policy as follows:
1. Type gpedit.msc in the Start Search box and hit Enter.
2. Click Continue when the UAC prompt appears.
3. Navigate to the following policy location:
Computer Configuration\Administrative Templates\System\Device Installation
4. Enable the following policy setting:
Turn off "Found New Hardware" balloons during device installation
Cheers, Mitch Tulloch, MVP http://www.mtit.com