System tries to boot to wrong HDD

[stickerhed]

I built 2 systems almost identical and one of them tries to boot to the wrong HDD. It will just sit there with "Loading operating system . . . I then hit reset and go into the boot setup (F12) and tell it which one to boot to. It will boot to the correct HDD then, but next time I turn the computer on it will do the same thing. What setting do I have wrong? Do I need to switch the SATA cables around or something? Any help would be appreciated.

System:
OS: Windows 7
MOBO: Gigabyte Z68x-UD3H-B3
Memory: 16gb Corsair DDR3
CPU: Sandy Bridge 2600k

thanks,

Doug

 

[Wamphryi]

You need to go into BIOS and position the HDD correctly in the HDD Order option. Make sure also the HDD is at least second (some like the DVD Drive ans number one) in the boot order.

 

[stickerhed]

Best answer selected by stickerhed.