death_scythe_2k, the idea that the id has to be 640 is just an assumption. ALL the original keys of win2000 had an id of 260 and the two original keys leaked have an id of 640. thus, one might assume that ALL winxp keys have an id of 640. which means, microsoft might blacklist all keys which have any other ID. the security algorithm would simply check for the two keys blacklisted by microsoft, the second step being the checking of the id of the present key. if it has any other id than 640, they would blacklist it and prevent the installation of the service pack. however, I just tested the key provided with the beta version of the service pack( Windows.XP.SP1-PsYcHoTiC ), and the id is 645! and people report successfull installation of the service pack with that key. which means the service pack beta blacklists only the two leaked original keys, but doesnt check the ids. however, this might change till the final release, which means you should let your computer switched on for a couple of nights, so that it generates a couple of serials. when the final service pack is out, you are then the first to be able to install it, using a key with id of 640. it costs you nothing, after all. just let the pc switched on, when you don’t use it.