So, why?! whats going on? how is svideo and composite a standard, that apparently some people didn't follow as a standard? :hammer:
The problem is probably that your monitor doesn't accept non-interlaced signals. Technically, standard-compliant NTSC or PAL video
has to be interlaced. The signals from a Mega Drive, Amiga, C64, NES, Super NES, PlayStation etc. etc. are not.
It's still disappointing though; you'd think monitor manufacturers would at least test with non-interlaced signals. On some TVs the S-video and composite inputs accept non-interlaced ("240p/288p") video, but the component video input doesn't. You'd also think manufacturers would include some kind of CRT-look mode with scanlines and handle 240p/288p images properly (instead of trying to deinterlace them) but I don't think any do.

If you play, say, Sonic 2 on the Mega Drive in two-player mode, that does output interlaced video. Can you get a picture on your monitor then? What about an interlaced Amiga Workbench?