Yeah now that the monitor decided to be normal I can see the green as well, and this can only lead me to one conclusion: it's a problem with the monitor, not the graphics card.
I tried messing with the colors already, won't work, the green slider doesn't affect the image on the screen when the problem is happening. I'm not an expert but I know that a CRT monitor has a ray gun that shoots electrons at a certain frequency (refresh rate) to excite the phosphor material that forms the pixels.. now if one of the three RGB colors isn't showing up maybe the electrons for that color have all decided to rest a bit.. I don't know, just a possibility! Anyway, it will probably be more expensive to get it fixed that buy a new TFT..!