|Product key will only work with certain types of Windows CD. The product key you have on the Laptop will be for an OEM version designed for that computer. The CD you have will be a different, possible a retail version or a different OEM version.|
As the company that supplied the original CD has gone out of business the sad fact is that, to put it bluntly, you are up the creek without a paddle.
Your only real option is you purchase a retail version of XP, not an easy thing to do these days.
Time to investigate the possibility of using a version of Linux.