James was on the right track. In my case, After Effects 7 was "orphaned" during installation by an unexpected restart. Although the rest of the suite activates fine, After Effects 7 displays a window upon launching titled: Personalize Your Software. It won't accept the Production Studio serial. I could not repair the installation. I could not uninstall After Effects.

The solution (for me at least):
Adobe gave me the following instructions on how to purge _ALL_ Adobe software from my system using the CS3Clean Script:

- Open My Computer
- Go to Tools > Folder Options, then the View tab
- Select the radio button for "Show hidden files and folders"
- Uncheck "Hide protected operating system files"
- Then go to Start > Control Panel > Add or Remove Programs and uninstall the Adobe products listed.

- Delete the Adobe folders at:
- C:\Program Files\Adobe
- C:\Program Files\Common Files\Adobe
- C:\Documents and Settings\(your user account)\Application Data\Adobe
- C:\Documents and Settings\All Users\Application Data\Adobe
- and delete Macromed from: C:\Windows\system32

- Empty the recycle bin

- First go to: <http://support.microsoft.com/kb/290301/en-us>
- On that page, about 1/4 of the way down, click on Download the Windows Installer Cleanup Utility package now Save it to your desktop. It should be named msicuu2 on your desktop. Open that file and go through the setup.

- When that is complete, go to: <http://www.adobe.com/support/contact/cs3clean.html> At the bottom of that page click on Download the Adobe CS3Clean Script for Windows Save it to your desktop. It should be named wincs3clean. Right-click on it and choose Extract or Extract All. Send the extracted files to the desktop. This should produce a folder also named wincs3clean. Open that folder and in there, open the file named CS3Clean. Proceed through that with the following responses, pressing Enter after each one: e, y, n, 4 (this is a hidden option), n, n, n, go - When it is done "press Enter to exit".

- (optional) Close everything up and go to Start > Run. In the Run dialog, type in msconfig, then click ok. Choose Selective Startup, then to go the Startup tab. On that tab, click Disable All. Then go to the Services tab. On that tab, FIRST check Hide All Microsoft Services, then click Disable All. If you have FLEXnet Licensing Service listed, recheck that one. Click Apply, then OK or Close and Exit with Restart. (end optional)

- After the computer has restarted, proceed with installation of your Adobe software. (part of the above optional section) When the installation is complete, go to Start > Run. Type in msconfig and press Enter. On the General tab, click in the radio button next to Normal Startup. Then click Apply and OK or Close.

NOTE: After the purge I reran my install with just one monitor attached (I have a dual screen setup).I also ran "msconfig" from the run menu, and ran in selective startup mode with all but the Microsoft services turned off. Everything seems to be going smoothly.

Hope this helps!