my motherboard's green led light glows little and my computer does not start. when i just hit the motherboard two three times from outside then light glows more and computer starts. Computer also turned off automatically at any time and green light glows little. That means when green light glows more, computer runs ok and when glows little computer turned off or not started. What should i do. need some suggestion urgent.
|>> Re: my motherboard's green led light glows little and my computer does not start
Not knowing the specifics of the motherboard and power supply, here's what I would examine/test first: the front panel power switch assembly (switch, wiring, connectors).
From your description, perhaps the dim green LED indicates your motherboard is getting "standby" power, and the brighter green indicates when it is getting "full" power.
Your report that it seems to unpredictably switch back and forth suggests a problem with the power switch assembly (switch, wiring, connectors) or possible intermittent short between some point in the power switch assembly and electrical circuit ground.
The response you reported when you "hit" the computer a few times is consistent with this kind of problem.
You might also try tapping on the front panel switch VERY lightly or gently putting your finger on the front panel switch and gently "wiggling" the switch side-to-side and see if either of those triggers the same problem...which would indicate the problem is likely the switch itself is broken or the wiring is damaged or shorting right at the switch.
If that doesn't work, and you can't test the entire assembly electrically, look for obvious signs of damage, loose power button, loose connectors/wires (both ends), shorts between connections and ground or the two "power" wires, the "power" wires "squashed" between the case or other items in the case, etc.
Note: IF something is loose does NOT mean that is the actual problem. It just means that because it is loose, there MAY be a problem with the way the manufacturer put the switch assembly together, or it has been damaged in some way, and closer examination is needed.
Less likely but still possible...the problem could also be a problem with the PSU main power connector or the PSU itself. The PSU main power connector and circuitry in the PSU are associated with the front panel power control, and damage, an intermittent short, or manufacturing error there could produce similar symptoms.
Much less likely but still possible (given the "hit" on the case symptoms)...is an internal problem with the motherboard itself. In this instance, an intermittent short-circuit between some point on the motherboard and something else might be the problem. This could be caused by poor manufacturing quality and/or improperly installed motherboard. You can try re-installing the motherboard being very careful to make sure no possible "shorts" occur. If you get to this point and the problem continues, you can also try running the computer with the motherboard removed from the case to see if the problem continues. But, if the proper safeguards and handling aren't used, doing that could severely damage the motherboard and/or other components in the computer, so unless you know exactly what you are doing I advise against that as it could be very expensive and there are safety issues as well.
added some details and expanded possible causes