Saw this post on another site (http download site) and thought that it might be of intrest !!!!!! as i was unaware that it was that easy to do...!!!! Im reasonably comfortable modifying these system file's as ill do a back-up first....hope its in the right section....
1 Browse C:WINDOWSsystem32driversetc
2 Find the file named "HOSTS"
3 Open it in notepad
4 Under "127.0.0.1 localhost" Add 127.0.0.2 w.ww.sitenameyouwantblocked.com , and that site will no longer be accessable.
is now unaccessable<--
For every site after that you want to add, just add "1" to the last number in the internal ip (127.0.0.2) and then the addy like before.
IE: 127.0.0.3 http://www.blablabla.com
here is some more info........http://www.mvps.org/winhelp2002/hosts.htm