What algorithm is used for choosing recently opened programs in Windows 7?
How can set Windows so it shows the last opened programs instead of the most frequently opened programs? Is there any utility or Registry entry to change its behavior?
Raymond Chen has blogged often about the constant tug of war between end users/MS and 3rd party apps with bloated egos, so I hope you're only looking to do this on your own system.
As mentioned above, obviously there is some sort of ranking algorithm used. I have previously read details about the data stored in the registry, the encryption used etc. on Didier Stevens' blog (search for the text "userassist" on every page using this tag to read the relevant posts). He also has a utility called UserAssist available that can decrypt and display all the data stored.
If you really want to, you should be able to build on that and figure out a way to modify the entries.