My computer malfunctions when i plug in my webcam?

ok so i have a webcam its by like gearhead or sumthing and it plugs into my usb and stuff my computer is a compaq precario cq50 11nr and its running vista it sumtimes works (well only twice) and when i plug in the usb it says usb device not recognized and its not the webcam cus i tryed it on my brothers computer and it works perfect so idk whats wrong i like updated a bunch of stuff and it didnt held so if you can help please thank youu