ORIGINAL: NCBrit
Does it have a product key sticker on it? If so, you do not need to purchase another copy of the OS. Contact Microsoft, and tell them that your disc is lost/damaged, and they will ship you another one. When you purchase XP you are buying the license, not the disc. As long as that sticker remains intact, you are ok.
As a computer tech, I can tell you that Microsoft will simply tell him to contact Toshiba. Product key or not. The XP disc comes straight from Toshiba.
If you do not have a product key sticker, you will have to purchase another copy of Windows. Having someone send you a cd will not help.
All he needs is the model and serial number on the bottom of the laptop. Toshiba will send the DVD for the proce of shipping, and maybe $10 for administration fees. I've seen this situation many times.