Bad picture

I need help before I go insane. I have Vista Ultimate 64 bit and Media Center is giving me so many problems. In media Center I am trying to watch Live TV but it looks bad. Downloaded Videos work fine and so do DVD's. But when I go to live tv thats where the problem is. Video is choppy it shows only in 4:3 aspect ratio and not 16:9 aspect ratio. The Actual Media Center is full screen just not the tv picture. I was using A Visiontek 550MCE TV card but that is only analog so I upgraded to a Gateway ASUS PCIe ATSC/QAM/NTSC TV Tuner Card and still the same problems. And no digitlal signal. I have RCN cable. In the bedroom I have a set top box but in the living room it just goes strait to the TV. Connected directly to the tv it works great I get HD channels and all(No payper view). I have the following set up:
Motherboard: Asus M3A32-MVP Deluxe/WiFi-AP
Processor: AMD Phenom X4 Quad-Core 9600
Memory: G.SKILL DDR2 PC2 8500 4GB kit
Video card: MSI RX3870-T2D512E OC
Tv Card: Gateway ASUS PCIe ATSC/QAM/NTSC TV Tuner Card
Old Tv Card: Visiontek 550MCE

I was even thinking about using a differnt program like beyond Tv. Please any help would be great.

The 4:3 ratio may be dependent on whats being broadcast. Also have you set your monitor/TV in MC settings to 16:9?

Choppy playback is usually either a) poor reception b) bad codec c) dodgy video driver.

Have you installed any codec packs? Tried a few different video drivers?