You don't need FFDshow - PowerCinema has a H.264 codec built in.
What type of video card do you have? If your machine is incapable of H.264 hardware acceleration then watching TV3 is guaranteed to cause issues as the 1080i feed is the most intensive to decode.
ldarbz: I am running it on my HP Notebook.
I think the Video card is Moblie Intel(R)915GM/GMS,910GML Express