This may be a silly question... however I recently purchased a used Optiplex GX270 with XP Professional installed, that comes with the original XP product key but and I want an actual installation CD. What should I do:

1. Just use any other another copy of XP and use my new product key if I have to reinstall XP? I am happy to buy a new copy if I have to... but I guess my question is can I use the product key that belongs to the XP on this computer with any random copy of XP Professional if I have to re-install XP?

or

2. Buy the CDs that match my product key from Dell. If so, I cannot find anywhere on the site to do this.

Thanking you in advance....