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?