Abstract: A heat dissipating system provides a fast heat dissipating airflow stream inside a desktop computer and thereby greatly enhances the heat dissipating efficiency of the desktop computer. The computer heat dissipating system includes a computer chassis which has a circular opening bored on its front plate, a motherboard which has a thermal module including a front cooling fan and a set of chipsets heatsink module installed on its top surface, and a power supply with a cooling fan. The thermal module, the chipsets heatsink module, and the power supply are aligned along a single heat dissipating airflow stream. The external low temperature air first passes through the thermal module and removes the heat generated by the central processing unit, further flows into the chipsets heatsink module and removes the heat generated by the MCH chipsets and ICH chipsets, and finally enters into the power supply and removes the heat generated by the power supply.