I figured out the problem was that indeed it somehow automatically kept applying the wrong resolution to my main monitor and switched off the second (that's probably what I did in the eyefinity control settings).
Than I switched to the windows display settings, where you can arranged displays like I actually wanted to in the first place, the problem here is the same it doesnt show you any options for the second display unless its connected. So I switched on the display, everything was nice and dark and did screenshots to see what options i got here. I figured out it tried to use my main monitor only with the wrong resolution (the TV-Resolution, too high for my nice CRT) .
Finally I found a way to maneuver through the settings blindly using shift+tab and and Enter combinations.
So... I hope this can either help others who stumble in the same mess or give a hint to these geniuses who create such awesome software.