i am wanting to reinstall win xp but need to know if my serial number is correct i have used belarc adviser it tells me the number but says it may be the manufactors number i have also used jelly bean keyfinder and it gives me the same number as belarc is this the number i use to register after reinstalling

"... i have also used jelly bean keyfinder and it gives me the same number ..."

I would use this Product Key.

Yes, that is the product key. It will be 5 sets of 5 numbers. If your computer came with XP then there should also be a sticker on the case somewhere with the product key.