I also posted this in the General forum but was hoping for more specific advice here as this is the best I can tell a motherboard-power supply issue. I need to try to explain the strange issues with my machine. I have an Asus P5Q-E with and an overclocked Q6600 (413*8 at 1.500V) that has been working well for some time (8+ months). I normally leave my machine on 24/7 but went on a long vacation and turned the machine off. I came back from the 11 day vacation and turned on my machine and nothing. The MB lights were on and tried pushing the onboard power and reset switches with nothing. I tried a few things but eventually ended up trying a different PS (only for a few seconds to see the fans spin up) and the machine turned right on. So my power supply was a few years old and I figured it had died. So my new replacement power supply arrives a few days later (a Fortron source 700W) and I plug it in and the machine boots right up. I had cleared the BIOS so needed to re enter all my settings and then got into windows with no problem. I then went about resetting my FSB speeds and voltages in the BIOS and booted into Memtest to ensure stability. I came back and the screen was blank, the machine was powered down but there were lights on my keyboard. So I thought maybe the overclock was bad and restarted with nothing. I became worried and again cleared the BIOS and pushed the power button-----nothing-----I sat starting to get concerned and out of the blue the machine turns on---what the hell?? So I got back into windows and started using the machine. I then rebooted and made what may have been the mistake of re-entering my overlclock settings and restarting. The machine again booted into windows. I went away for a while (20 minutes) and came back and the machine was off. I since have been unable to get the machine to start with the new power supply (I also tried the old one with nothing). I did have another older power supply available and have since connected that for a brief second and it still works. With the other two dead power supplies, the motherboard lights are on when it is connected but the machine absolutely does not turn on, the fans don't spin and nothing happens. So it seems to me that my previsouly stable computer with absolutely no issues has now apparently started destroying now two power supplies? Does anyone have any idea what is going on? I am assuming this must be a motherboard issue--but why and why now? I am thoroughly perplexed and what appreciate any possible help. Also, since this may be a shorting issue, does anyone have experience replacing power supply fuses?