Redhead

I have a Sentient H.264 DVR with a 160GB hard drive and it is not working properly. When plugged in the screen shows the images from the 2 cameras I have connected but non of the buttons to access the menu work and the device does not seem to be recording either. The lights for HDD, NET and REC are not working at all. Usually the HDD and REC lights are both lit. Anyone got any ideas on how to fix this?