My computer won't turn on?

Computer wont turn on?

• Inspiring PC tech here. I'm working with a family members computer while going to school for pc tech school. This computer im working with, has had a sad life. Lightning hit my families house. The computer worked for about a year and a half after that with no problems. Now the computer is failing to turn on. I checked the power supply, all the connections are running the right voltage, and all the fans are running.(PSU, video card, and case fans.) So it's not the PSU. I removed the video card and tested it in my computer, worked like a charm. Ram is seated fine and worked in other computer. I did remove all the unimportant (floppy, hdd, and network card.) So what im left with is the CPU, cpu fan and Mobo. When the PSU is plugged into the mobo, nothing works. however i used a wire to ground and power to test all this. However the cpu fan would on occasion turn on. but 90 percent of the time it wont work at all. So i removed it and tested it in my other computer. the CPU fan worked every time there. So my question. Am all i left with is a bad mobo connection, or a fired mobo? What else is there to test, and how so? Only thing I can think of doing, is to replace the mobo, and see if that solves the problem.

• Answer:

  Could always simply be a short somewhere, or perhaps the CMOS needs resetting. First and foremost, reset the CMOS jumpers. Try turning it on. Could really be that simple. Next, try removing the battery for 30 minutes, replace the battery, reset the jumpers again, fire her up... If still no joy. I'd remove everything from the case, sit the motherboard on some cardboard, with one stick of RAM in the leftmost slot, CPU & cooler, and nothing else. No HDD. No opticals. No GFX. No WiFi. No keyboard. No mouse. Nothing else. Then, plug the power supply into the MB, CPU and CPU fan ONLY, touch the two power pins with a screw driver, and see if it turns on. If no joy, then a short isn't the problem. So, move the stick of RAM to the second from left slot, try turning it on, if still no luck, move it again. Keep doing that until you've exhausted all the slots with no success. I would then try a different PSU, just to ensure that that isn't causing the issues, but from the sounds of things, you've already tried that. After you've reseat the RAM in the first (leftmost) slot, you know that the DIMM sockets on the motherboard aren't the issue. You would then normally try switching the CPU. I am assuming however, that you don't have a CPU that matches that socket available? If not, then you can't really test it. Which leaves the only option of trying a new motherboard that's compatible with the RAM type/speed and CPU socket. If it reaches this stage and still won't boot, I would feel fairly certain that the 20/24 pin power socket on the motherboard was toast. If you're feeling brave you may be able to reflow the circuitry on the motherboard (you'll need a heatgun capable of reaching around 350*C to melt the solder, and some flux), but that's not really a permanent solution, although, if you're going to buy a new motherboard, then it's worth a try really. I hope it's simply a short or a CMOS issue, but this is the way I'd test a build showing these symptoms. Hope this helps! .