A heat dissipating assembly for dissipating heat from a graphic card and a hard disk driver, includes a heat sink for contacting the graphic card and a fan duct fixed on the heat sink. The housing having a placing space is connected to an opening end to enable the hard disk be placed into the placing space, and a door plate is further installed at the opening end to avoid the hard disk departing from the housing. Suspension rods, which are suspended from lifting jacks, are then connected to the 8th floor unit and jacked up, while floor units made for lower than the 8th floor are connected on the ground to form a multi-floor unit.