I just made myself a slipstream sp2 xp cd with nlite, and while I was at it I changed the pid on my cd, and now I can't activate. So, I'm going to have to reinstall again... but here's the trick. I've never had an original oem windows xp pro cd.. I have a stack of licences from salvaged computers but no cd. I made my own previously using Pid=55276OEM and that worked before, but being an upgrade-oem pid. I changed it when I made my new cd (sick of providing my 2k disc) to Pid=51882OEM and that failed to activate, being a retail-oem. What's the proper pid for a true oem cd? I'm looking for one that will definitely work with sp2. Will my upgrade-oem pid work under sp2 (worked on sp1)? If I change it to a true oem-oem pid would I lose the ability to upgrade? I'm trying to keep as much flexibility in installation options open here since I have 6 licenses and no idea where 4 of those are going to eventually end up. I really don't want to (can't) lose the ability to do upgrade installs.