hi . i have tried a lot of things to instal win xp from a usb stick ,on my toshiba nb250-107 with no results ... to find out that nb250 series has problems in booting win xp from an usb stick .... after that i tried from an usb cd/dvd-rom and it works like a wonder... so if you really want xp on your toshiba nb250 try it

bt keep in mind that you may have problems with wifi signal cause it is very low on xp... good luck ..