WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system.

Delete the appropriate key under the following registry key:
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall

You will find a long key name if you click once on it the preview pane on the right side will show tom clancys..blah blah

Then put you cd1 in the drive and see if it gives you the option to install again.

Kind Regards