Video Search keeps freezing and locking me out.

I have a 4 channel Bunker Hill Security System, I'm trying to retrieve video from a couple of days ago through the dvr, when I go into the video search and type in the date I am looking for, I enter the date, I hit menu to get out of the date and go to hit search, my system makes a beeping noise and then locks me out of everything, I dont have a lock or pw setup so idk why it's locking me out,what do I do? I have an issue and need the police to review the footage but can't get into it...