Hi Anna,welcome to TZ first of all.What kind of USB drive do you have?Pen,hard drive,cd or dvd?Did your drive come with usb drivers?If so install or reinstall them.Another thing I thought of is the version of your drive ie.(1.1 or 2.0)versus your computer's usb capabilities.If your machine is only capable of usb 1.1 then a usb 2.0 hardware device could make xp bluescreen or restart.