Problem: I'm having a difficult time diagnosing my sister's computer. Her computer had recently stop working; nothing will start up when I hit the power button. I had tried to analyze the situation by opening up the case, and everything looked fine; but of course, that's coming from an untrained eye whose scope of knowledge on computer hardware is very limited and elementary. But the one thing I had noticed is that when I tried plugging in the power cord in the power supply unit, the LED light on the PSU would light up for a second then turn off (and flicker when I try to jerk the power cord around). Nevertheless, I haven't ruled out other suspects. I have been searching around the internet and realize that the computer my sister has (emachine) is notably renown for motherboard failures. That being said, I was wondering if you guys could help me with the situation. P.S. One more thing, the computer stop working around the time we had painters around the house. I assume when they were painting they had unplugged the computer then plugged it back in after they were done. I don't know how much of a relevance this is to the situation at hand, but decided to mention it.