My PC was running fine until I tried that auto O.C. programme that comes with ASUS A.I.suite. I set it to 3.6 and then pressed the select button which would normally turn the PC off and on again. this time when it turned off it stayed off and the mobo board lights went off as well although the battery was still connected. The CPU i5 3570, MOBO Asus MAX V and RAM are only 2 months or so old with very sparse use. The battery is about 4Yrs old Antec 650W . CPU is water cooled, no leaks. Before being turned off the PC was running all the night before and all day the next so rough guess 36 hours which is normal as I usually leave mine on 24/7. It was just web browsing and watching films and downloading some stuff for the most part so nothing too strenuous going on before the problem. Any ideas anyone ?