Windows XP - HELP?!?!

Last year I crashed my system and brought it back up with a complete new install. The only Dell Windows XP disk I could find was the one for my desktop. I re-installed it (since I couldn't find the other). Now my laptop says that it is a pirated copy and won't let me update anything because of verification. Here is my question. How hard is it to reformat and bring everything back up since I no longer have my Dell disks (they got lost after we moved). Can it still be done. I am not above buying a new version of XP... Thanks.

 

Also, what are my other options?