I'd very much like to block tor from my pc for administrative reasons. Any specific tips on how I could go about doing so?

Any help is appreciated. Thanks.

Disconnect the PC from the internet....

Problem solved

Prevent it from running. It seems to get past my firewall.

Isn't that kind of the point?

Would there be anything that prevents tor from being run or installed at all. Can an external firewall block the client vidalia or something?

cant you just like uninstall it or move it to an external disk or something?

You can tell TOR to only use ports that your firewall permits.

I have done that but my sibling seems to run a portable version.

You should be able to block it from accessing the internet through your firewall. I don't understand why it can't be blocked. What firewall are you using?

Forgive me, but I'm still a bit confused. If you don't fire up the game, does it still access the internet? Is there a process involved with the game that starts up when you start your machine? If so, you should be able to prevent that from happening by adjusting your startup processes.

Tor is an encrypted browser. It seems to run off any portable device and that is where the problem is. I am using windows 7 and a windows firewall.

Tor is not a game - https://www.torproject.org/

With a GPO probably, not sure if you need to use full paths.
Or a script that checks every X seconds or minutes and kills all tor.exe processes, but that script could be killed by anyone that has permissions and know-how.
So assuming we're talking about Windows, your best bet might be a GPO and some user restrictions assuming that your 'sibling' uses another account.

LOL - okay, forgive me for being dense. I saw tor and was thinking of the game. Heh. Perhaps there's something you can do in your router setting to block it?

If you have a professional edition of windows it should be easy to use policies to block tor.exe or any process you want from running for any given user you want - I used to screw with my housemates and block everything they liked from running if they left there computers running and they could never figure out how. If you have a normal edition of Windows (Home edition etc) this is not possible though.