A computer includes a chassis, a motherboard, an air guiding member, and a fan. The chassis includes a rear wall at a rear side thereof and a sidewall at a lateral side thereof. The rear wall defines a plurality of inlet holes therein, and the sidewall defines a plurality of outlet holes therein. The motherboard is received in the chassis opposite to the sidewall, a heat sink is installed on the motherboard for dissipating heat generated by a processor mounted on the motherboard. The air guiding member is received in the chassis at a front side, for guiding air drawn into the chassis through the inlet holes toward the outlet holes. The fan is used for drawing air from outside of the chassis through the inlet holes, and blowing the air out of the chassis through the outlet holes.