For many causes we need to block different website.

For Ubuntu

Open a terminal and follow this steps:

$sudo gedit /etc/hosts

then open the hosts file  and write your desire website

Say for you want to block facebook

127.0.0.1 www.facebook.com

and save this file and test it on your browser.

For Windows XP follow the following steps:

1. Click Start->All Programs->Accessories->Command Prompt.

2. Click Command Prompt This will open a DOS command window.

3. Type: notepad C:/Windows/System32/drivers/etc/hosts

4. Locate the line 127.0.0.1  localhost

5. To block the website facebook.com for example, just add this text under 127.0.0.1 localhost:

Say for i like to block facebook write down this

127.0.0.1  facebook.com

For all facebook site block:

127.0.0.1  *.facebook.com

And save this file and test on your browser.

Are you user on ubuntu and and your net option and volume control already hide?

Open your terminal and sequentially run the following command:

$ gconftool --recursive-unset /apps/panel
$ rm -rf ~/.gconf/apps/panel
$ pkill gnome-panel