Invalid windows key?

[cozm01]

I reformatted my laptop and reinstalled Windows XP using a XP cd I had for my PC. During installation I could not enter the Windows xp cd key that is stuck to side of laptop, I could only use the key which come with the XP disk. So I installed and everything went fine..

but now I can't update to SP2, it says my key is invalid.. any clues? perhaps a program to enter the key on side of laptop exsists?

 

[cozm01]

update: I found a way to re-enter product key, but it still saying its invalid!.. even though I have authentic sticker on side of laptop with product key.