pls have a look at my thread regards no video capture on w7 and 64 bit system.
there may be a problem with ANY video edit software in the w7 64 bit arena.
32 bit w7 worked fine for me with all video software apps.
IF YOU HAVE 32 BIT W7 TRY HDVSPLIT.
It is free and simply captures the video to hard drive.
It is a very small file size and can split scenes.
is your system 32 bit?