Can you tell us if you just went to power it on and now you have the problem's. Trying to get a background to how we got to the problem.
It's the pc giving any beeps as it sits there with a blank screen.
Unplug keyboard and mouse.
just want to check a keyboard has not gone faulty on you and preventing post boot. With out the keyboard you should still get a post boot and memory check. Then the error no keyboard error, which is good as it could narrow the problem down.
The rule of thumb in this situation is to unplug one thing at a time until you're left with only the power cable to the motherboard, after that your pretty much narrowing it down to a bad board.
just check if the fan is spinning up on the processor as that one is important and should spin up at max speed until the operating system says slow down.
As previous with the memory remove all of it, swap it around.
It could also be a power supply problem as you have a 5v supply for the fans but 12v and I think a 7v for other bits. So that could say why some power is reaching some parts.
All you can do is be methodical in your process.
Keep up the effort, it will be something stupid like a keyboard or mouse or failing USB connection or the board is on its way out.
Hope that helps
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