The key in registry is a key doesn't require any activation if CD contains OEM's bios files (so, you must have dell OEM windows and you must have dell materials too). Key on the sticker is an original key which works on regular windows xp cd but to activate it you must phone to microsoft. The WPA.DBL method is completely obsolete since service pack 1. My solution (I work too in computer shop in france ...) : Create a multi boot cd with windows home & professional regular with all informations generic (same User name & same settings) and I have blanked ProductKey, I enter the key when is needed and I activate later (or the final client activate itself, it's not hard to do ^^). The bad/fun part is for drivers & softs !