BleepingComputer.com: Strange power problem

So, I was infected with a trojan a couple weeks back and I recently decided that I wanted to format my computer rather then deal with the virus. However, my compute began shutting down randomly some times after being on for only 30 minutes, and some times for many hours, or not at all. Then, my machine developed another problem. Every time I try to turn it on, it comes to life for just a split second, and then shuts down again. I have to press the button 20-30 times in succession to get it to turn on, each time I can hear the innards of the computer revving up just a little longer.

Tried a different power supply yet?

Louis