So, you guys are the experts, and that's what brings me here! My system of 5 years died! I custom built it back in 2005 and everything was running great until the other night! I had discovered nTune from Nvidia and ran it. a few hours later ( I had gone to sleep for the night and left the computer on. I did this every night) it turned itself off. Now when I hit the power button it turns on, then turns off almost immediately! I removed every connection to the Mobo except the 24 and 4 pin connections, disconnected the HD, HDD's, RAM, Video card, etc... only thing connected was the mobo and the CPU, same problem. I then removed the Mobo battery for 10 seconds or so, put it back in, moved the reset CMOS jumper over for a few seconds to reset that, disconnected and reconnect my PSU, and still same result. I then purchased a new CPU and installed it, still will not turn on. I tested my PSU with my Multimeter, and all of the Voltage readings are within their specs. I am at a loss here at what to do!
Running an auto overclocking program over night was not a good idea on such an old system, check your motherboard and look for any capacitors that are bulging or blown, it may have overstressed and killed something.
I didn't run the program overnight... I ran it, it did it's thing, and my computer was sitting idle with nothing running. it shut off maybe 3 hours after I had ran the program... will go over the checklist and check over the comp and get back to you.