im booting Ubuntu 12.04 from my usb stick n everything was working great but then eventually the other 2 usb ports stopped responding when i plugged something in, yesterday both worked until i restarted ubuntu now its the same, i know nothings wrong with the ports cause i can plug my usb stick that has ubuntu into one of the other 2 turn on my laptop n it boots up fine but the other 2 usb ports that arent being used arent working even if i have something plugged in them before turning my laptop on, any ideas?