I recently purchased a Venturer 22' flat screen tv, and we have cable. . Lines scroll down the screen when I'm watching Tv, playing video games and watching movies. Is there anything I can do to make them stop? Their really annoying and don't give the "flat screen experence".
What type of cables are you using to connect the television?
You should seek to use cabling in the following order of quality:
2. DVI or VGA
3. Component video or coaxial from a digital source.
5. Composite video
6. Coaxial from an analog source.
If you're relying on 4, 5 or 6 it's no wonder you're seeing interference. Avoid them if at all possible, even for standard definition applications. A high def television will show the inadequacies of a low quality connection even more clearly than a standard TV. For playing video games you should at the very least be able to employ a component video connection. If you experience interference with that or better then there is something wrong.
For your cable connection, you can try to set up digital reception of as many channels as possible if your TV has a digital cable ready (QAM) tuner. Alternatively you can request high definition service from your cable company. It may cost a bit more, but they'll likely provide a high-def box with quality connection ports along with the service upgrade.
You have a video ground loop. This may be caused by a ground problem in your cable system. Since you get this line on other sources ie DVD disconnect the RF cable wire from your TV or cablebox when on that other source and see if it goes away. If it does call your cable provider and they should be able to fix it. If they don't you need to get a ground loop isolator or in line surge protector. This goes in between the RF cable and the cable input of your cablebox or TV. Try www.centronics.com model 634 if the cableco won't take care of it.