if you don’t know what is ad hoc it’s better that you don’t continue reading.
if you are trying to create a new ad hoc network but you can’t find it in the “Network and Sharing Center” first you should check that if your hardware can support it the create it.
so open the windows command line using admin.
the type

netsh wlan show drivers

and check for this line

Hosted network supported  : Yes

if it says no, you need a hardware upgrade
and if it’s yes continue.
then you should create it using the fallowing command line (you can change the ssid to what you what because it’s the name of your network and the key is the password that other people should enter if they what to connect to it.)

netsh wlan set hostednetwork mode=allow ssid=mynetwork key=lame password

after that you should start your network because the command line before was only to set the properties. So this it how to start it:

netsh wlan start hostednetwork

and if even now when you see your ad hoc network you can’t connect to it go to it’s properties under sharing tab allow people to connect to this pc to get internet.