No problem. If you don't have an open cable line you will have to split the line. It's just a PCI card that routes the video signal to your video cards memory(very little processor usage). I prefer this scenario because I have no love for ATI products. Sorry to all the ATI fans, I just don't care for the driver support. Stick with Nvidia. The image quality on the Hauppage is pretty good, especially if you don't use an extremely high resolution.
BTW: I just started posting here. Can someone tell me why my posts state that I am an XP Home user, not Pro. Thanks