Service Packs and Product Keys

XP keys are finicky, SP0 keys may or may not work with SP3, though theres no harm in trying. Is your system in a working condition?- if yes, you can try create a disk:

How to Create a Bootable Windows XP Setup CD/DVD from a Pre-loaded/Preinstalled Windows System (howtohaven.com)

Another alternative is to simply order recovery disks from the relevant OEM for your model, that'll ensure compatibility. These are cheap and you'll also get a disk.

You can also try download an SP0 disk from the web, you'll need to hunt.

All the XP have had new HDD installed, I searched on the net for a Legal XP Download... did not get any promising results.
TBH I don't want to use torrent site as I don't think they'll be clean... can anybody recommend where I can get the ALL Windows XP Version from?

Thanks,

Is there no Universal Disc for Vista and Xp?

IIRC, I have answered that question in another thread started by the same OP. Vista has universal disks just like win7 but not XP.

If you download the XP ISO from the web to reinstall with Product Key on COA sticker, check the comments and rightclick scan the ISO with your AV and Malwarebytes. You can also check the HASH against official HASH for that version to make sure nothing is added.