Software for surveillance cameras?Active Webcam?

Hi. I have 8 security cameras, my computer has a dvr that came with the software Pico 2000 however I had trouble installing it and recognizing the cameras. I tried Active Webcam and it recognized the 8 perfectly.

However I need to record the 8 cameras for 24hrs and keep the videos for 15 days or so bit when I record the video files are huge, I cant find how to compress them or other option. Also the quality of the videos is not enough. Im looking to be able to have a better resolution while im monitoring and also smaller video files. I just use this computer for surveillance and i dont need any internet features. Anyone knows about another software that can work for me? or how to fix the active webcam? Thanks a lot