This paper uses CFD to identify a cooling solution for a desktop computer. In this modern world speed determines everything especially desktop PC, CPU have been popular. The computer revolution is growing rapidly in almost every field. CPU is the electronic components, which produces a lot of heat that reduces the performance. In this study the forced convection cooling of heat sinks mounted on CPU are investigated. The design is based on total chassis power dissipation. This represents significant power dissipation for the chassis components (Main processor chip, other chipsets North bridge heat sink and South bridge heat sink) the main processing chip has fin attachments (heat sink) over it for heat dissipation. There are many designs of heat sink to improve the efficiency, few heat sink designs are selected and analyzed, which would be give the maximum heat dissipation. There are many ways of cooling such as air cooling, heat pump cooling. The modified fin geometry with air cooling which is more effective and economic, since the water cooling requires water pump, a separate cooling system for coolant and a separate flow circuit. The air cooling is attained by using a cooler fan above the heat sink fins. The effect of heat dissipation and heat sink geometries are numerically analyzed by computational fluid dynamics software and fluent. The best heat sink design is selected and modified so as to attain the maximum heat dissipation. The design is able to cool the chassis with one case fan and the power supply fan. A ducted 80×60 mm CPU heat sink is able to meet the CPU temperature specification. System level design improvements were made to provide better cooling for AGP and PCI cards.