Paul,
Since you have verified in the Registry that Autorun is enabled make sure that your CD-ROM driver is current:
1) Click Start, right-click My Computer, and then click Properties.
2) On the Hardware tab, click Device Manager.
3)In Device Manager, expand DVD/CD-ROM drives, and then right-click the CD-ROM drive that you want to update. Click Update Driver to start the Hardware Update Wizard, and then follow the on-screen instructions to install the latest driver for your CD-ROM drive.
Take Care,
Richard