To set DVDs to play automatically

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On the Tools menu, click Options, and then click the File Types tab.
In File types, select the DVD Video check box.

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You must be logged on as an administrator or a member of the Administrators group to complete this procedure.
To play DVDs, you must have a DVD-ROM drive, and a software or hardware DVD decoder installed on your computer. If you do not have a compatible DVD decoder installed, DVD-related commands, options, and controls do not appear in the Player and you cannot play DVDs. By default, Windows does not include a DVD decoder. For more information about DVD decoders, see Windows Help.
This feature is only available on select versions of Windows. For more information, see Special features.