PROBLEM SOLVED! My GTX690 has 2 DVI-I and 1 DVI-D. My Monitor is connected via DVI-I. I have also connected my TV to the GTX690 via one of the two DVI-I. So when windows starts the ROG-Logo and the 4 colors of windows come together gets displayed at the TV, after that the signal is switched to the monitor and i see the Login-Screen. Now i moved the cable connected to the TV to the other DVI-I-Port and as result everything gets displayed at my monitor. Thank you all for the answers! Hopefully this solution can help other people!