XP key

Hi, I was wondering. My boss has let me have one of his old PC's that were just sitting in a cupboard so I can give to my son. Now obviously I decided to wipe the HDD and reinstall XP. The PC case has an XP key sticker on it, could I install a version of XP Pro I have and use that key? The PC its self was one of four that were supplied with a server. I think (as I can only find one XP Pro disc) that they used a multi use licence or something.
Does all that make sense?

try it, if not use another key.
That is what i do trying to get into my house.
it requires some fumbling.

Is your windows legit?

Uh, no. Thats why I was wondering if I could use the key on the case as it is legit.

If it is a mass produced PC then almost certainly the key will be tied to a particular OEM version of XP.
Without that version the key will be rejected.

Why bother you " may " have to phone Microsoft to validate . Have done it myself as have others on this forum , better to google a student key and be done with it .