If you are using the 4channel version (2xcap3004 or something like this) then you can get into the DVR SYSTEM folder, and look for a app called "start.exe"
there you can modify YUV or RGB way of capture (choose RGB since its more friendly)
if you bought an CAP120N16 (or something from the LIVCAP family), you need to buy an accelerated graphics card (ATI / NVIDIA) and look for the right drivers, once i had a problem with the latest drivers, but found that the oldest version available did the job.
Good Luck
