Windows 7: How can I block users from Facebook

I don't have a Facebook account, nor do I want one because I see what it does to the rest of my family (including my wife, omg it's out of control). They've already taken over my PC in the office and when one of them is on that one of the kids logs on with my laptop. The only sanctuary I have left is browsing the net on my iPhone.

I'm in the process of building an HTPC for the living room and I'd like to block Facebook from this PC altogether. If my wife found out she could play Farmface (or whatever the hell it is) on a 42" plasma my world would be over. I want to nip this in the bud...

I would add an entry to for facebook to your host file to block it, the following tutorial will show you how - Hosts File : Use in Windows 7 / Vista

127.0.0.1 facebook.com

I've tried that on my office PC way back when I first installed Windows7 and it didn't work very effectively.
If I just blocked facebook.com it would work but if someone clicked a link that was say: facebook.com/username/comments it would let them in. Once they were in they could browse their profile and have full access.
In other words there appears to be countless ways someone can get into facebook without using the "front door".

I've also used free trials which worked okay but then I'm the d!#k for using apps to block my family and then they all hate me.
I just want something non-intrusive, something I can play dumb and be like, "I dunno why facebook isn't working?"

No, it redirects anything that starts with facebook.com so anything after that wouldn't matter and would still be redirected, to make sure facebook was completely useless even if by some chance they did get to it then add all the following entrys:-

127.0.0.1 facebook.com
127.0.0.1 www.facebook.com
127.0.0.1 login.facebook.com
127.0.0.1 www.login.facebook.com
127.0.0.1 www.static.ak.fbcdn.net
127.0.0.1 fbcdn.net
127.0.0.1 www.fbcdn.net
127.0.0.1 fbcdn.com
127.0.0.1 www.fbcdn.com
127.0.0.1 static.ak.fbcdn.net
127.0.0.1 static.ak.connect.facebook.com
127.0.0.1 www.static.ak.connect.facebook.com

Sweet, I'll try that.

Is there any reason a Hosts file would be overwritten? Say by a software or Windows update or something?

None that I have ever known.

HostsXpert would restore MS's original Hosts file ... if they knew about it.

Yeah, but the user would need to know the hosts file had been changed and also the software to reset it, if somebody actually had that much knowledge then they would just wipe the entries themselves with notepad

I'd recommend two accounts on the HTPC - one as administrator, and one as a standard user. Have the main 'Media' user as a standard account, so anyone who uses the HTPC can't mess it up (that proved very valuable on mine!).

Secondly, have a look at parental controls. I've never looked, but there may be some settings in there you can apply to the Media user account to prevent browsing, or only allow certain programs to run, for example.

Buy them beer