OK, I think I kinda understand.
You're subscribed for high-speed internet service.
But since the cable co. can't disable the cable TV signal, you're getting it for free (albeit not very well).

Other than trying a new peice of coax, I'm not sure what else to recommend. Maybe call the cable company? heeheehee!

There are many illegal decriptors out there on the internet, which I know you have access too, However it would be theft.

Another option:
Get a splitter and split off signal from your tv that gets satellite and attach to the other tvs.
Then, hook up a radio frequency remote controller to the satellite box. The other tv's become a "slave" to the first tv but you can control it from a different room using the radio frequency remote. One caveat - you can't watch two different shows with only one box using this setup.

If the picture is scrambled you probably have a trap on your line that blocks the TV signal. I've had Comcast internet in several locations and they have done this to me once. Sometimes the installer puts it on, sometimes they don't. Short of removing the trap if you have access to the outside box, which is very risky there isn't anything you can do. Even an illegal box as someone mentioned won't help as that whole frequency range is filtered out. The best way around this is to subscribe to their basic cable. Internet is $10 more a month if you don't subscibe to cable TV as well and the basic cable is $10 so its a wash. This will give you locals and a few more, but thats it because they can also put a trap on the line for this that will filter the expanded basic channels. In my case they didn't put the trap on so I get channels 2-99 and from what I hear its a well known secret that they rarely do.