Howdy.  I have a dimension 4600.  The computer was working without problems, I almost never turn our computers off unless we are going away or a storm is coming.  Turned the computer off Friday night by start, shutdow, turn off computer.  Went to turn it back on on Saturday and nothing happens when I push the on/off button.  Tested the power supply by unplugging the power from all but one hard drive and jumping the balck and green wires on the main power plug,  power supply fan spins and the hard drive spins up.  If the power supply or the mobo went bad I would have thought that I would be having intermittant problems or the computer would have just shut down.  I am hoping that it is the on/off button.  Any way to troubleshoot the on off button or any other ideas what might be the problem.  Thanks in advance.  Gene