Re-loading Windows XP SP2

Hi---Have a relatively new Dell XPS 410 and would like to start fresh with an XP re-install---have the disk sent to me by the Dell with my machine---have done this on my older machines with no problems but have been reading in these threads something about not being able to get Microsoft updates if I re-load???---am not sure I understand---shouldn't I just be able to drop in the disk and start fresh?---thanks for any help

 

Thank you!---the sticker is there---these old eyes can just make out the code---your reply is much appreciated