My Dell Inspiron desktop computer is about three years old. When I was installing my printer with the installation CD, I noticed that the tower was making an unusually loud whizzing noise. The printer installed successfully, and the computer was still functioning normally. I turned off the computer afterward. When I pressed the power button the next day, however, it refused to turn on. Absolutely nothing happened. I already tried opening it up and cleaning out the dust. Also, the green LED light in the back is lit.

It's been three days. Help?

Where was the noise coming from?