Cecep1974,
Please take the server to a Minimum to Post Configuration. That involoves downing the server and removing everything but the following -
System board
I/O board
Risers
Processor (CPU1) with Heatsink
Power Supply
Power Distribution Board
At least 2 DIMMs in sockets A1, A2 (lock-step pair) to POST
Control or I/O Panel board
Control Panel w/cable
After that then boot and cycle and see if it Posts ok, then see if you can power down as well, without pulling cord. If it boots and reboot please add the removed hardware back until it fails again.
Let me know what you find.