I've got an account on a Windows 2000 Terminal Services machine at work. For some reason it won't allow me to change the file associations. I need to change the program that opens EML files, which are Outlook Express mail files. Since generally I'm looking at this mail because it's spam or viruses, there's no way I'm letting Outlook Express come within 10 feet of it. That would just be an invitation for disaster.
So here's how to change the file assocation via the registry instead.
Add a new String Value with name "Application". For the data, put the name of the program you'd prefer to use, such as "gvim.exe".
That's all it takes. Pretty cryptic, huh?