Am currently facing a problem with my home PC, whereby upon switching on, all the lights switch on normally (HDD, DVD-drives, PSU), then just seconds later, it switches off by itself, and again some seconds later, starts to switch on by itself, but again goes off (in a loop). No beep sound whatsoever.
I can share what we do in the shop with such a PC. Ready? We downsize it. Any component that isn't required to get a BIOS screen is removed. If that doesn't bring it back we remove the case because a lot of homebuilt PCs have extra mounting posts and create issues.
So if you downsize it to just motherboard, CPU+HSF, one stick of RAM and PSU without a case and it still doesn't stay up, it's one of those 4 parts.
rproffitt, did as you suggested, but first went for the "paper-clip" test with the psu. its fan started to run as soon as I switched the power on. Decided to connect only motherboard and psu, and switched on fine. Plugged all my internal hardware again, and the PC started properly.
So am still unsure on what caused this issue in the first place... Will keep a watch for a few more days...
@R, that usually points to assembly errors. Most common find is an extra mounting post in the case randomly touching the back side of the motherboard. Drives the owner nuts as it works then not and takes it in and it works.
I've had similar problems when either the CPU or RAM would overheat. As a Linux user, I had access to the sensors tool and could monitor the temperature of these parts. I found that the RAM was overheating, but because I was only using 1/2 of the available slots, I staggered the spacing and the problem went away. Now, it runs nice and cool! At 10+ years old, it is still a kick-### server! Dual quad-core Intel chips and 8GB of RAM. Also, it, being custom built, has a 1000 watt PS. Never go cheap on the power supply!