I am running Red 3GL and all used to work fine, but now if I put it on openGL mode no footage shows up on the composite screen, turn OpenGL off and it all works, I am using an ati x1900 card and ythe Boris test says it's fine for openGL.
Has anything been changed on this system. such as a driver update for the video card? Is this happening when you run RED as standalone or as a plug-in (or both?) Are you running another application simultaneously which may be preventing RED from accessing the video card?
I'd suggest reinstalling RED and seeing if that takes care of the issue. Please let me know if this works to correct the problem. Meanwhile let's see if any of the folk in our tech support lab have seen this before and if so what the cure for the problem was.