I found this in a few different places around the 'net - hopefully it's helpful:
Turn Off Autoplay for Program CDs
How can you stop Windows XP from launching program CDs?
- Click Start, click Run, type GPEDIT.MSC to open Group Policy in the Microsoft Management Console.
- Double-click Computer Configuration, double-click Administrative templates, double-click System, and then click Turn off autoplay.
- The instructions on your screen describe how to configure this setting. Click Properties to display the setting dialog.
- Click Enabled, and choose CD-ROM drives, then click OK, to stop CD autoplay.
This setting does not prevent Autoplay for music CDs.