I have to agree, the first MC was much better than the second, but I do not have a copy of the first. Plus I doubt it will run on XP anway, though there may be user made patches or instructions on how to run it on XP.
Just re-installed Mech Mercenaries yesterday and started a new campaign, wow this game was, and is still so much fun. One of my favorite things to do is able to customize your Mech however you want.
If they make this new Mechwarrior anything close to the way Mech4 was, it should be a good game. But Mech2 is where the best game play and story is, that was more like Mech sim more than anything.
Edit: Looks like a full version of Mechcommander (1) is
here.
I am guessing it is legal, since it has been years since the game came out and now is just free.