I was looking closely as to how you worded your problem, and your saying that once the t.v is back on once being shut off that you get no signal to the t.v. I'm wondering that if maybe you right click on desktop and hit refresh maybe it would pop up. I had a set up one time like yours, but it didnt work out as well as i thought it would with what i wanted to do so i dont use it anymore. That was just an idea, and maybe go into your video card settings and look for a refresh option or something like that or change display modes back and forth. Also there is a neat utility called powerstrip that is free for download that has a lot of different options for displays and what not that might assist you with some other options for your card that might help you get it working from the computer side without a reboot. Hope that helps you some , I'm not a real pro with the whole computer to telivsion problem thing since i didnt use it for long , but thats an idea worth trying.
