There's a product key on the bottom of laptop, 5 sections of numbers etc.

Ok that's good, make a note so you don't have to disturb the laptop when installing and away you go.
Like I say set the boot sequence to cdrom first, make sure you do not alter any other settings then save and exit.

Here's a site to show you in more detail.
Scroll down the page to where it says "XP Clean install".
XP Clean Install

Thanks for you help

I've just read on another site i use that this is a widespread problem with some laptops and may be a false positive. Don't know what to do now lol

At the end of the day it's up to you Paul.

Thanks again for all your help

Your more than welcome, glad to have been of service.