I'm trying to work the bugs out of an installed projection system in a large room. First off, don't ask why it was installed a certain way, because I didn't do it and already want to rip it out and redo it, but money was in issue in the install, so it was done the cheapest way. There are 2 projectors mounted to the ceiling with VGA and composite video runs to a central location. The VGA cables are plugged into a splitter/amp and the video cables are just combined into one jack and plugged into an A/V splitter and amp. My problem comes in with the computer I'm using in the system. I noticed ever since I started using the PC (was using a laptop before) that I have some pretty bad interferance in my video signal. There's what looks like a scan line that runs across the video screens from top to bottom (or bottom to top, it goes both ways). The speed it moves varies. It seems to be some sort of electrical problem because when I turn the PC off and use a laptop running on battery, there is no lines. The lines also show up when using the video input (composite cable) when the PC is on. If I turn off the PC, the lines go away in the video input (there's a VCR and DVD connected to that input). So somehow the PC is introducing electrical interferance into the video signal. Is there a good way to fix this? Right now all the video cables are run very close the the PC, so I guess I could try to seperate things some. Spread some equipment out and see if that does anything. Would putting a 2 prong cheater plug on the computer do any good? I know it's not a great idea, but I really need to find a way to clear this video signal up.