What is it you don't understand? If it's in reference to win XP's SP2 update, it can cause problems with connections & you'd need to re-check all your firewall configurations & possibly do more such as apply special patches to repair the damage SP2 has done. There's no need for anybody to update to SP2!!! It's intended for big companies with major networks, but even then its caused major problems b/c like most things MS does, it contains bugs & behaves in ways it shouldn't. MS never tell you about these things. It has cost big business many millions of dollars in lost revenue & all due to MS's lack of competence.