Mate, you're gonna have to be a lot more specific. Since the problem lies in video, we need to know the make, model, and age of the video card as well as the same information for the rest of the components in the system.
But based on the information provided so far, it sounds like your video card has an issue. A tint of any particular color can indicate a pin that isn't making contact (in this case, at the card end of the cable), the port could be coming loose from the video card, or the card could be on its way out.
I think this because:
1. You've tested a second monitor with the same result (main reason)
2. You've tested another cable (also very convincing)
3. The AV-in on the monitor works fine
