I ran the registry cleaner in aggressive mode and here are the things that it broke:
1. The Open/Explore and Open All/Explore All context menus in Start > All Programs no longer work. They do not do anything when clicked (I'm talking about right-clicking on the folders in the All Programs main menu, e.g. Startup)
2. The Play default context menu for AVI files which normally opens Windows Media Player no longer works (doesn't do anything when clicked). This was fixed by re-installing WMP10, just simply re-associating AVI files with WMP didn't fix it, something more serious was broken.
3. MediaMonkey no longer starts, the process runs and exits right away. A reinstall of MediaMonkey fixed it.
4. WinKey + L stopped working (lock/fast user switchin). Not sure this is related, it may or may not be.
Any ideas which keys were removed that may be causing this? There are just too many to go through and I can't submit the backup due to privacy reasons.
thank you