The original disk was dead. Anyway was a little small in capacity, but it had been xp pro. The disk i have in now is from another computer, cleaned down , erased and formatted, so is basically a new disk. The licence from Microsoft agreement must be Ok as the system is using the key on the PC case. So to crarify. The Computer Case has the Key sticker, The original HardDisk gone and replaced with a bigger completely clean hard disk. The CD is one ( you say OEM ) which I had here. I am not concerned about Microsoft as the system was already using XP Pro .