autocad 2013 file wont open

so i recently started taking an architect autocad class. our first project was nothing special but for some reason whenever i save it on my removeable usb after working on it at home, it wont open on the schools computer. it doesnt open as the specific file i wanted, but instead it opens up a blank file named drawing1.dwg. the file name does not even come up at the top of the screen. anything would help. thanks