Does the Toshiba have a CD Key sticker attached to it? If so, is it readable? Can you read the 25 characters? If so, then you need to find a Windows XP OEM CD and then you can install with that CD using the Windows XP key on your laptop. If you want to just install a new CD, you can use that too, but if you buy an upgrade, you must have a Windows 98, 98SD ME or 2000 CD. The short answer is that you can install with another windows CD.
Also, make sure that you are able to download all the drivers from the Toshiba website for your laptop. Windows may not provide all the necessary drivers for your computer.
I had to do this with my Compaq and then had to download the sound card driver to get my sound back.