Actually, I think MAYBE I have some hope for you.

Assuming you reinstalled Windows XP overtop of itself, it MIGHT have made a new account for you (in Windows - not Freelancer) and so your old My Documents (where the Freelancer saved games are) is there, but under your old account name or a backup account name.

Freelancer save games are normally stored under My Documents -> My Games in a Freelancer folder, so what you'll need to do is locate this folder with your saves in it and move it to My Documents -> My Games.

To find the folder (hope you're good at Windows), right click your start menu and choose Explore. You should see a list of things under Documents and Settings (Administrator, All Users, Your Current Name, etc.). See if your old username (or a backup copy of it) is there and check the My Documents folder under it. My guess is, from experience, Windows simply renamed/moved your whole account slightly (including My Documents) and made a new one for you to avoid problems. If this is the case, just move the whole My Games folder from My Documents in the old account to My Documents in the new account and you should be set.

Good luck and I hope this helped and I got what I was trying to say across okay.