Things you will required :
1. Laptop having Windows 7 with Wireless Card
2. Wired Internet Connection
1. Turn on Wireless feature of your laptop and then Open Network Connection
2. Click on " Set Up New Connection or Network "
3. Click on " Set Up wireless ad hoc "
4. Say Next . . Next . . and the enter your network name say "Injector" and set security type for your wireless network. Generally select "WPA2". WEP can be easily cracked. Put password for your network and then say "Save this Network" so that you will not need to configure network again and again
5. You are done !! You can see your wireless hotspot in Network area
6. Search for your network from any other laptop or mobile and Enjoy !!!
To remove your network Just navigate to "Manage Wireless Network" in your Network Sharing Center.
Same things you can do if you are having Windows XP/Vista in your laptop.