Hi,
Another possibility is that the DVR port is flaky. WITHOUT powering down the camera or PC, hook up the camera output to a portable composite monitor, or switching it with another port. See if the problem follows. Try this at the DVR end of the cable and then at the other end, directly at the camera output. I have one customer with a GV900 card, that this periodically happens to. It needs a cold boot to fix. Centrlizing the power to the same UPS as the PC, appears to have solved it for them. Ground loops?
Good luck.
