Thanks Ryan for the information,
my actual problem is as below
I am trying to create Wireless Network Connection Between Two lap tops to share Internet. One has Windows Vista OS and other has Windows 7. I created ad hoc network on one lap top by following the above shown steps. After that I tried to connect to this network from other lap top. However other lap top recognized the connection, sometime it fails to connect to that network and sometime after connecting to network, Internet have not worked.
I have tried creating ad hoc network first on lap top having Vista OS and then on the other Lap top having Windows 7. But till now I am not able to find the solution to the above problem.
I will be really greatful , if you could give me some inputs for this.