So as a service tech, I have had to troubleshoot many a bad power supply or motherboard but here is an error I have not encountered yet. The tower I am troubleshooting is 64-bit HP compaq dx2250 microtower. I dont think it has vista on it any longer but it doesn't get that far. When mouse, keyboard, VGA display and power are plugged in and I press the power button, the fans spin up and the machine begins to power up but nothing comes on the monitor. (Monitor is on correct input setting and verified to work). Also note that there are no addition display chips installed, nor have there ever been any. So I power it down to verify RAM is seated, HDD plugged in, all cables and buses are correct and they are, but when I press the power button, there is no response at all this time no matter what I try. I even bypassed the button with another switch in case the relay was bad and no luck. So I left work, traveled out of town, and a week later I come back and give it another try. Here's what is strange, like a de javu, the machine does the same mysterious thing where it powers the first only, and no luck the subsequent times. It seems the power supply is ok, at least enough to power it the first time, and the motherboard LED is on. Obviously something has gone bad but what could it be? has anyone encountered a similar issue?