Blank Screen

Hello,
OK, my computer was running a little slow so i decided to restart, during what should have been restart everything sounded fine except the power supply, also nothing came on the screen, but the power supply would seem like it was trying to power in burst from the sounds it was making. Another interesting fact is the power supply switch located on the back of the computer i can turn that off and the computer will still be in this false running state, so bottom line is everything sounds like its starting up normal and all the other fans are spinning but nothing on the monitor and the power supply sounds funny...