Windows 7: I want to block all access from a computer in the LAN

I want to block all access from, as in completely locking out, a computer in the LAN behind the Internet router that we all share. I don't want that machine to have any access to my Win 7 computer at all, since the user of that machine might going to try hacking into the LAN network. I want to know how to set this up in the Win 7 firewall. Thanks!

hello and welcome,
you just disable the sharing folder or you can set the security permission to who can access into your PC.
Sharing and Permissions

Does it help even further to select "public network"?

The way the permissions are set up is to either allow "Everyone" or "Nobody" access to file shares on LAN computers with nothing in between. This is not as simple as the previous posts would suggest I can assure you.

Conversly, Windows firewall is only set up to allow a programs or features through it, there are no settings to block individual users.

Some routers have a guest account which allows you to set up a wireless guest connection that is outside the LAN. That is about the only way to accomplish what you want. On my router you can only do this if the untrusted User is connected wirelessly.

There might also be a way to do this using the untrusted users Windows Live account name but you would need to set this up on both his machine and your own and it's not exactly a reliable method at this point and it's a pain to set up.

The download link in this walkthough doesn't work but you can get the specific download "either 32 or 64 bit" when you click on the "add an online ID providor" link as you go through the listed steps to set this up. I havn't tried this yet to confirm if it works so good luck.

Neowin.net - Windows 7: Link your online ID and share files in Homegroup

You may or may not like Comodo's products, but their firewall can be told to prevent access (in or out or both) from any machine (or machines) in your network.
And its free.