Lee Schierer in McKean, PA
It could be a bad power supply or a dead hard drive. Since you have another CPU, you could see if it has two hard drive power cords and an extra data cord. If it does you could move the hard drive from the dead computer to the one that works. If the hard drive works, retrieving your data should be straight forward. If the hard drive does not work at all, there are companies that can recover the data from the disks, but they are not cheap.