I hoped to be able to play Mechwarrior 4 (my current favorite game) with the newly-released Inner Sphere Mech Pack - but I believe that due to Microsoft's addition of a security/anti-piracy program called C-Dilla, it is not working on my system.
Getting it to install at all was an adventure - you have to uninstall both Mechwarrior games (Mechwarrior 4 : Vengeance and MechWarrior 4 : Black Knight. You then reinstall the first game and run the latest patch - sp3 - then install the second game and install the patch for it - sp1bk. After this, the game plays fine, the patches work well, and everything is speedy.
However, once I install the Inner Sphere Mech Pack, the process of loading the game slows down by a factor of ten, and it goes away after the first play - so the second time I load the game, the IS Mech Pack materials are not available. Oh bother. And as a bonus, it still loads ten times slower than before. I think there is a problem with C-Dilla and Windows 98se, as that seems to be the only common thread among the 3-4 people I know of that have this problem.