Hi there thanks for the reply!
I'll be honest, I am looking for a new DVR card as after doing some research and tinkering it seems that this is where the problem lies, that's as far as I know. I don't know a lot about security systems but all I know is that we have a store with 16 cameras (that only record video), with the wiring leading upstairs into 2 VGA's in the DVR card, then there's a VGA coming out of the graphics card which goes into a video splitter box, the splitter box then goes back down to 3 TV's downstairs. Of course there's another VGA coming form the computer's onboard graphics going into the computer monitor too.
At the moment, after the power cut, the awful DVR software either crashes (no longer have the installation discs or anything) on launch with the DVR card in, or no image shows at all. This system was already in place when the shop was purchased.
We would just like to get a basic but decent system working, and its quite urgent now too. Thank you in advance for your help!