A lot of people are having problems with the 003x versions of the BIOS. If you now have version 0028 I would sugest to read the forum posts (search for DZ68BC) and decide yourself. Once you upgrade from 0028 to a 003x version you cannot go back.
Try using just one DIMM. What CPU do you have installed?
Firstly, thank you for your quickly response.
vbarderks: i`ll try to upgrade the bios by myself as soon as i can boot the MoBo.
nails: I tried to use a single card but it's not work. I'm using a i5 3570K. I don't know what is the bios version and i'm thinking how can i will upgrade it without boot sequence or some other init screen.
Thanks again and best regards,