In this Instructable I will show you how to make a simple portable fan. Warning before taking apart the computer power supply you must unplug the power supply or else you could be really painfully shocked or even killed just from touching one of those silver plates which are heat sinks I learned that first hand but luckily I wasn't killed. You should also use a grounding wrist band with a built in resistor and make sure you keep your hands and tools away from the big black things, they are capacitors which can still hold a charge of about 200 volts at 5 amps which can easily injury or even kill you!! I am not responsible if you get injured or killed.
But you can easily overcome this by using a different fan from inside your computer.