Tiny store XP on hidden partition of the drive and charge £60 quid for the backup program to recall it.
If you format the drive this will be gone forever with no chance of recovery. Little chance of buying the recovery disk now Tiny have gone into admin.
1. See if you can borrow a tiny restore disk from someone, this will restore to factory original.
2. Format the drive, borrow a full XP disk from someone BUT use your product KEY on the sticker on your PC when you install.
3. Buy a full XP CD with lisence