How to set up TKS cable with Windows Media Center?

I'm having trouble setting up TKS cable (on base) with Windows Media center. I can get some of the Germany channels to show up but when I try to change to channel it stops working. I have a sony vaio VGC-LV140J desktop with built in tv tuner. I have a digital and og cabe input. I can only get picture with the og, but still it doesn't work for long and i can't see any American channels.