HumBug--Removing items involves going into the Registry and is a bit involved. http://support.microsoft.com/?kbid=258860
This also works in WinXP.
I wonder if it is worth it.
Changing the program that automatically is used to execute a file type is easy. It depends on what version of Windows you have.
Assuming you have WinXP, right click on any file of that type|Open With|Choose Program|either highlight one of the programs offered or click Browse and choose the program|click the box at the bottom "always use the selected program..."|OK.
I never learned how to change the order of programs in the list.