Similar issue here.
Suddenly no connection, I took all apart.
I connected the board to the power with no fan and no HD:
- the Power indicator green led (LED 8) and
- the ethernet port yellow led are blinking,
- with a clicking sound.
All of them at a same time, a little bit more than 1 Hz.
No serial connection.
Molex has no 12V and 5V is floating between 0 and 2V.
I already tried pushing and holding the reset button with power stable and power rising, nothing.
Fun thing when I disconnect the power the clicking and blinking will slowly fade away.
I think she's gone.