I am attempting to fix a friends HP a1747c desktop PC. The problem is when you hit the start button, nothing happens, no fans, no lights, nothing. I have replaced the Mobo, tried powering up "bare bones" still nothing. FYI the green LED on the PSU itself illuminates brightly when the ATX cable is NOT connected to the Mobo. When I do connect it, then plug in the PSU the led lights very dimly or not at all, this happened on both the old Mobo as well as the new one. I have not updated the CPU (Anthlon 64 4600+ 2.4GHz) yet since that will be a pricey fix and I am not sure it's the solution. I also have not replaced the PSU since everything I read online thus far says if that LED is functioning the the power supply is probably still good. There was a previous thread about this same HP model with the same problems. I pretty much did all the steps recommended in that thread with the exception of replacing the PSU. One final note, my friend told me she plugged a heating pad into the same power strip as the PC and everything else was connected to, this may sound a little out there, but could that have been a factor in all of this, she told me the problems started immediatly after that.