Computers built between 1999 and 2007 have been failing at very high rates due to a defective part. Thanks to a faulty chemical recipe (that was apparently based off a stolen trade secret), capacitors like these often fail after a few years of use. They will either 'pop' with crusty material forming along the 'vent', or the vent will 'dimple'. The top of all capacitors should be flat. These very inexpensive parts can cause computers to not power on or behave erratically when in use. So if your computer starts acting strangely – a quick visual inspection can tell you if this is the problem. We have most common types of failed capacitors in stock and have performed dozens of these repairs. You can get your computer back up and running, often for less than $150. For more information, see http://en.wikipedia.org/wiki/Capacitor_plague