I have received a bunch of calls lately about dead PC’s that will not power-up. In almost all of the situations it has been due to a dead power unit. This is a common problem among machines 3-years and older. Whether you leave your machine running all the time or turn on/turn off the device, the power unit is a very vulnerable part. Add to that heat, dust, power surges and power outages and it is a ripe candidate for failure in many systems.
That said there are a few simple, cost-effective tips you can try to get more life out of your power unit. In each of the systems I recently worked on there was one constant - lots of dust. Most people place computer towers on the floor or tucked inside a desk, etc. This attracts more dust and does not allow the system to vent the airflow properly. One solution is to place the PC tower on a riser or something that gets it directly off the floor. Try to let the tower have sufficient airflow. I know this is not always possible.
Another suggestion is to clean the tower regularly with a compressed air canister to clear dust, etc. from clogging up fans, motherboards and drives. Pay special attention to both the CPU fan and the power unit fan making sure both are free and clear to do their jobs. Need some compressed air or unsure what to look for? Below is a link to buy with a graphic to assist you if you are looking for some in a local store: