MechWarrior 4
 

Here is a link to a No-CD patch for the release version of MechWarrior 4. It appears to work for me, and I bought my copy just recently (it's not a "test" version, which some of the existing copies on GCW appear to be for).

http://mektek.net-games.com/mech4/patches/mw4nocdv1.zip

Of course, this is so that I can keep my originals in a safe place. By the way, the site also has some cool development stuff related to MechWarrior 3, 4, and more.