An expansion bay for a computer system having a rotatable fastening mechanism is disclosed. The expansion bay includes a bay housing having two facing side walls, a front open end and a bottom panel. A front tab and a rear tab extend from the interior of one of the side walls. A tray supporting an expansion component has a guide block with a threaded aperture. The tray may be positioned between an open position and a closed position. The rotatable fastener mechanism moves the tray into and out of the bay housing. A rod is inserted through apertures of the first tab and the second tab, allowing free rotation of the rod. The rod includes a threaded exterior section to rotationally engage the threaded aperture of the guide block. A knob is attached to an end of the rod to allow a user to rotate the rod and move the tray.