Hello F4RIO,
3 beeps in a loop mean the processor is not recognizing the memory.
I would need to gather your processor model and Brand name and model of your RAM memories. We need to know if they are fully compatible.
I would recommend to downgrade the BIOS to version 70. Please use F7 method.
Instructions for F7 BIOS Flash update
http://www.intel.com/support/motherboards/desktop/sb/CS-030144.htm