Help! Problems connecting PC to TV

[NuNuNYC]

Whenever I try to connect my computer through S-Video (with AIW Radeon), and my laptop (Radeon 9100), I get these vertical lines that scroll from the bottom up to the top of the screen on my Sony HDTV Projection TV. Also, when I plug in th audio (red/white) to my TV, I also get a pretty noticeable humming feedback noise. I was wondering if anyone knows what the problem could be why I get the vertical lines that scroll to the top of the screen.