Use Notebook as a WiFi Router to share Network

If you don't own a wifi router but you have more than one computers to share the network and
if you want to share the network on one computer over wireless,
then you can follow these steps the create a network sharing over your wireless computer (in most cases a notebook)

This is technically called computer-to-compter (ad hoc) network.

These explanations are for Windows XP

1. You need a wired connection on the computer which has wireless card. We will call this computer as host
   You can install a wireless card on your desktop and share the Internet connection on the desktop computer too.
   Let's set up the host computer now:
2. Open your Network Connections. To do that
   a.Start > Connect To > Show All Connections
   b.Start > Network Connections
   c.Right Click on "Wireless Network Connection" or "LAN Connection" icon on System Tray > Open Network Connections
   d.Start > Control Panel > Network Connections
   
3. First go to Properties of Local Area Connection
   Right Click on "Local Area Connection" > Properties
   Go to "Advanced" tab
   Check the box for "Allow other network users to connect through this computer's Internet connection"
   Under "Settings" you can further configure your sharings and restrict some of the services shared if you like
   
4. Click OK and window will be closed. Back to Network Connections.
5. Go to Properties of Wireless Network Connection
   Right Click on "Wirelss Network Connection" > Properties
   Go to "Wireless Networks" tab
   If there are wireless networks detected, you'll see a list of these networks displayed.
   And you might have list of wireless networks listed under Prefered Networks section, Remove all networks from this list.
   
6. Click on "Advanced" button
   Here you will select "Computer-to-Computer (ad hoc) networks only" and uncheck the box for "Automatically connect to non-prefered networks"
   then click "Close"
   
7. Now we will create our access point on this host computer. On the "Wireless Network Connection Properties" window's Wireless Networks tab:
   Click on Add button under Preferred Networks section
   Here we will configure the network settings;
   a. Enter desired Network Name
   b. Check "This is a computer-to-computer (ad hoc) network; wireless access points are not used"
   b. Uncheck Network Authentication or Choose as Open
   c. Enable Data Encryption or Choose WEP as your Data encryption
   d. Create your Network Key which would be the password for other computers to connect to your network. So make your key as strong (Upper and lower case letters, numbers, underscores, etc.) as possible
   Two possible screen shots are like these:
   
8. Click "OK" annd you'll return back to Wireless Network Connection Properties window
9. Now we will set up the network on this shared network.
   Go to "General" tab of this properties window
   Under "This connection uses the following items" Find Internet Protocol (TCP/IP)
   Choose "Internet Protocol (TCP/IP)" and click "Properties" button
   
10. Here we will set the range of IP addresses to be assigned on the network.
    Choose "Use the following IP address:"
    As an IP address, enter "192.168.0.1", or it can be 192.168.1.1, or 10.10.0.1, etc.
    Subnet mask will appear automatically as 255.255.255.0, which means you can have 254 computers connected to your network each with ip addresses of 192.168.0.2, 0.3, 0.4, ..., 0.254
    Here if you set the subnet as 255.255.255.255, then no other computer can obtain ip address because you limit the range with only 192.168.0.1
    Click Here to learn calculation
    Then Click "OK" buttons until each window is closed
    
11. Now you can connect to this host computer from another computer (which we would call as "client") and share the Internet connection
    To do that, simple search for wireless networks and connect to the one you named before and use the key, just like you connect to any other wireless network.