Picture cuts out after three seconds

Thanks, but, I have NO problem with the AUDIO. The PROBLEM is with the VIDEO. I don't need audio to make the picture do anything. I have ONE DVI and TWO HD15 inputs on my monitor. I can route sound through the monitor but I choose not to. It will never have any effect on the picture in the first place. Now, do you have any advice on the signal dropping out after three seconds forthe picture? Thanks in advance for any help you can dig up. Thanks, but, I have NO problem with the AUDIO. The PROBLEM is with the VIDEO. I don't need audio to make the picture do anything. I have ONE DVI and TWO HD15 inputs on my monitor. I can route sound through the monitor but I choose not to. It will never have any effect on the picture in the first place. Now, do you have any advice on the signal dropping out after three seconds forthe picture? Thanks in advance for any help you can dig up.

..........And, just to be perfectly clear, I DO have the Comcast box plugged directly into the monitor via a DVI-D cable that came with the monitor. It works fine with all the outputs mentioned in the original post. The fact that I DO ge the nice, pretty HD picture for the three seconds proves that the display is completely capable of displaying the signal. I called Motorola and they also agree with me that if the signal displays for three seconds, it can display for three hours just the same. The Motorola tech told me it must be in the Comcast programming they do after they receive the boxes. I hope this makes my question clear. ..........And, just to be perfectly clear, I DO have the Comcast box plugged directly into the monitor via a DVI-D cable that came with the monitor. It works fine with all the outputs mentioned in the original post. The fact that I DO ge the nice, pretty HD picture for the three seconds proves that the display is completely capable of displaying the signal. I called Motorola and they also agree with me that if the signal displays for three seconds, it can display for three hours just the same. The Motorola tech told me it must be in the Comcast programming they do after they receive the boxes. I hope this makes my question clear.