How do I reinstall windows xp....

Hey guys I am having problems installing Battlefield 2 and Half-Life 2 and I have a feeling its related to a corrupted XP install. I just reformatted a week ago and I cannot get these games to install so I'm down to the last solution. I'm wondering if their is a way to reinstall windows xp without losing anything. Some kind of reinstall of the system files? Thanks for the help in advance.

im thinking doing a "repair" or "upgrade" and it should keep your current info. It just reinstalls the XP files.

Just do a repair install.