I'm not too familiar with these DVR's. What kind of motherboard is used in this unit? What I do with other DVR's is I pull the CMOS battery out for 30 seconds or so, then reinstall it. By doing that it will reset any passwords that have been set up. Just to advise you, before you pull the battery out be sure you have unplugged the DVR from the wall and that you have no power running through the DVR, and that the DVR has completely powered down. If your not sure what the CMOS battery is, most of them look anything like a nickel of even a quarter. It should be located directly on the motherboard. let me know if you have any questions, or if this helped out!
Thanks,
Roger