Well,
1. Just take out AC adapter and press the power button for 10 second, again connect the AC adapter and try again.
If still same issue
2. Remove and install again all RAM and try again. If still same issue
3. Remove all installed RAM, then power on machine again. Is the machine giving beep sound?
If Yes: This is a RAM issue
If No: The possible issue is Mother board.
Well,
1. Just take out AC adapter and press the power button for 10 second, again connect the AC adapter and try again.
If still same issue
2. Remove and install again all RAM and try again. If still same issue
3. Remove all installed RAM, then power on machine again. Is the machine giving beep sound?
If Yes: This is a RAM issue
If No: The possible issue is Mother board.