If you want to go back to Windows XP you must purchase a copy and perform a clean installation of it, which will erase the installation of Windows Vista along with any files and settings you may have created. If you go this route, be sure to backup everything you hold dear before proceeding.
P.S. Have you tried contacting Toshiba to complain, or disabling unnecessary startup items?
I just got a toshiba satellite laptop vista on it. It looks extremely slow. Starting takes 2 min and shutting down takes 3 min. Activate explorer takes 30 sec. Specifications of the laptop is 1.6GHZ duo with 512 MB ram. It looks it needed at least 1GB or more memeory. Any info about downgrade from vista to XP? I do not think it is gonna be changed when I put 1GB ram into the laptop.