Hi, Anyone know how to reformat a laptop with Vista back to XP.

Same way you do any computer:

Ensure you have all the necessary XP drivers for all the hardware devices in the computer,
Buy a legal Windows XP license and installation disk,
Follow the instructions in the Windows installation guide for a "new" install.

Only thing not in the guide is to ensure your BIOS Setup Menu is set with the CD drive ahead of the HD in the boot order.

Thanks Can I use my desktop copy and get second licence.

Thanks Can I use my desktop copy and get second licence.

You mean just the piece of paper? Sure, but I think you would have to do that from MS directly and unless you are buying lots of copies, I don't think you will get a good deal. I recommend you look at OEM licenses on-line. They will include a disk, which is better if you decide to sell or give the computer away and want the person getting it to be legal.

Do understand you are talking about going back to an operating system that was designed for the security environment and hardware technologies of the last decade. Is that what you really want to do?