Stafford911:
You can use any key as long as the version is right, XP home, XP professional, media center... (They cannot be mixed). However, the activation part is the killer. Microsoft mix your motherboard and hard drive (maybe other devices as well) to generate a key, that will store into Microsoft’s database alone with your product key. Most key can only use once.
It is not legal to give you a key. Call Microsoft and tell them your situation, they would help from there.