Format & Reload Windows

My situation is this. I have a laptop with XP Pro OEM. From what I have read I not only need an OEM disk but also the matching service pack(SP1,SP2,or,SP3). The laptop shows to be SP3, but I think it has been updated from a previous version SP1 or SP2. I have two questions.

1. How can I tell what version XP Pro I have on the laptop?
2. If my XP Pro SP1 cd doesn't match, can I still use it, and how?

Thanks

You can format and reload XP with an earlier SP, but you will have more updates to reload at Windows Update.

Does the sticker with the key say OEM? If so, then the disc needs to say OEM also.

For starters, ignore poiuyt's post and don't click his .gif link - he won't be here much longer.

PhilFrisbie's point was that you couldn't put any old XP disk into your laptop if it's already installed elsewhere or you'll have activation problems. You an install a system with SP1 and leap straight to SP3 and 125 subsequent updates as soon as you get the drivers together to get online.

If the laptop was an OEM installation, you may have a recovery partition that will take it back to factory settings with no lost driver issues. What I can't understand is you say in Post #1 that "the laptop shows SP3". If you can see Control Panel, why reinstall?