Ga-Z68XP-UD4 Beep and Boot Loop

[tussee]

Hello, I have just bought the parts for a new PC
Setup is as follows:

Gigabyte GA-Z68XP-UD4 (rev. 1.0)
Intel Core i5 3570 - 3.4 GHz
Corsair Vengeance - 16 GB : 2 x 8 GB - DIMM 240-pins CMZ16GX3M2A1600C10
OCZ Agility 3 Series - Solid state drive - 120 GB
2x Seagate Barracuda 7200.12 - Harddisk - 1 TB - intern harddisk
BN090 PSU Be Quiet! 450W System P

I started assemblying it all. and it went good.

Untill I was ready to start the system.
Everytime I power the system on I get the one OK beep, EXACTLY 15 seconds later the PC reboots. I don't get anything on the screen (using the onboard HDMI or using the GFX card from my old PC - Radeon HD 5770

It follows this cycle:
Power on ----> 4,7 seconds ----> 1 short Beep ----> 15 seconds ---->Power off ---->5 seconds ----> Power on

The Cycle repeats itself indefinately.

After it did that I decidet to unplug all drives and disks. --->same problem.

After that I decided to remove the MOBO from the case and try with only 1 ram stick in ----> same problem

I tried it with the ram stick in every slot. I tried it with the other ram stick in every slot. ----> same problem

I tried an overnight BIOS/CMOS reset no battery in for 18 hours. ----> Same problem.

I have run out of ideas?

Excuse for my bad english. I'm from Denmark

Best Hopes

Tussee

 

[tussee]

Forgot to tell that I tried with my PSU from the old PC with same result

 

[tussee]

Please! any one have any suggestions as to how I make this work?