i am having trouble to get any picture from my s-video out to my tv. i have the cable connected and the tv on the right station then i have reatarted my PC but it does not seem to recognise the tv. i have tried to search for new hardware but nothing is registered. i have tried changing the refresh frequency to match the tv but i can not get any visible signal. there is some signal because the tv screen changes when i plug in the cable. do i need to switch the output on like i do with my laptop?