A couple of weeks ago, my Dell E510 started shutting off randomly. After it would shut off, the front would start flashing a yellow light, but the computer could be turned back on by holding down the power button and pressing it again. About two weeks later, this solution stopped working, and the pc would always show a blinking amber light, regardless of any attempts to turn it back on .
After several days of researching the problem, I found out that it could be a power supply. I ordered the exact same PSU that was previously in my pc, and installed it. To my surprise, it worked! Sadly, after 20 minutes of use, it shut off and I am now unable to get it to turn on again.
I have cleaned the entire case, and there are no corroded or leaking pins or caps on the motherboard. I just recently replaced the CMOS battery, so I don't think that is the culprit. I have tried fiddling with the wattage switch on the back of the case, but that didn't seem to do anything for me. I also tried resetting the CMOS memory by using the 2-pin jumper plug. Nothing seems to be working.
Is this a motherboard problem, or something else?