i would recommend installing sp1 only as soon as windows xp is installed. otherwise, installing service packs in the middle of the stage, would cause errors. it happened when i used windows 2000 professional. i was using it for a while. and then sp2 came out. after i install it, the system became unstable. i think it is cos a large number of system files gets updated and the other software is not ready for it. once install sp2 soon after installing windows 2000, and then install all the other rest of the software, everything seemed be all right
