CaseBuy's EZ Power Supply Tester
 

If you've ever had your computer lock up on you, spontaneously reboot, and other peripherals stop functioning
on your PC, a likely culprit is the power supply. But how do you test if you power supply is faulty? Well you could try
another power supply, or even easier you could use CaseBuy's EZ Power Supply Tester. This handy little gadget lets you
test your power supply by hooking it up to the tester and in moments the tester will show the results if it's faulty or not.

Direct Link: http://www.techtastic.ca/reviews4/ezpower.html