Understanding AutoPlay for a USB Device
AutoPlay settings for USB devices are located in the located in the Control Panel. To access and change AutoPlay settings, click on the Windows start button and select Control Panel. Next, click Hardware and Sound and then AutoPlay.
For each type of media that may be inserted into your computer, there are multiple options for how to handle such media automatically. By default, when a USB drive is plugged in to a computer running Windows 7, it is examined for the prevalent types of media (photos, movies, music, etc.) stored on the device. After it has been scanned, the AutoPlay window appears, and asks you what you would like to do.
Since USB devices typically store a wide variety of media, there isn't a dedicated area for selecting a default action for USB devices in the AutoPlay settings window, as there are for DVDs or CDs. Instead, you select how to handle a USB device depending upon what types of media are stored on the device. For instance, if a USB device primarily contains photos, it will be handled under the "Pictures" setting in the AutoPlay settings window. If a USB device contains many photos, music files, and some video content, then it would likely be see as "Mixed content" and would be handled as such.