A - Editing the hosts file should do it... add the website url manually or with an editing software.
Windows 7 - Hosts file location
C:\Windows\System32\drivers\etc\Hosts
Windows 7 – How to locate and open the Hosts File
http://helpdeskgeek.com/windows-7/windows-7-hosts-file/
Hosts File Editor - To automate the Hosts file edition.
http://hostsfileeditor.codeplex.com/
B - Blocking websites manually through the Control Panel... Internet Options \ Security \ Restricted Sites \ Sites... copy & paste the website address. This should work with Internet Explorer.
How to Block a Website on Your Computer
http://www.wikihow.com/Block-a-Website-on-Your-Computer
C - If you're using a third party web browser, the most popular Browsers have Add-Ons/Extensions or Settings you can download or enable.
For Firefox; install "BlockSite 1.1.8"..
https://addons.mozilla.org/es/firefox/addon/blocksite/
For Opera; Site blocking with Opera’s URL Filter API.
http://dev.opera.com/articles/view/site-blocking-with-operas-url-filter-api/
For Chrome; Use BlockIt
http://www.guidingtech.com/3431/block-certain-websites-in-chrome-web-filter/
install a website blocker... to install. l have to add a website blocker Add-On