I have a powermac 7500/100 and when i was trying to use toast deluxe 4 to run some 'toast files' the computer was stuck many times. I was using the power button to turn the computer off but nothing was happening and the only way to turn it off was to pull out the plug from the socket. Unfortunately the powermac doesn't work now. It doesn't turn on. What is the problem? The power supply was burned?