An electronic device has a removable module installed inside. The removable module includes a first surface and a second surface. The first surface is adjacent to the second surface. At least one first fastener is disposed on the first surface. At least one second fastener is disposed on the second surface. A printed circuit board and at least one track are installed in the housing. At least one rail has at least one third fastener and fourth fastener. The third fastener is inserted into the first fastener. The fourth fastener is inserted into the second fastener. The rail is disposed between the track and the removable module.