Sorry im a new at AD HOC so ive binged it and found a wizard to install it on Windows 7, now ill try to find it in the help files - so here we go - hope this is helpful -
Set up a computer-to-computer (ad hoc) network
An ad hoc network is a temporary connection between computers and devices used for a specific purpose, such as sharing documents during a meeting or playing multiplayer computer games. You can also temporarily share an Internet connection with other people on your ad hoc network, so those people don’t have to set up their own Internet connections. Ad hoc networks can only be wireless, so you must have a wireless network adapter installed in your computer to set up or join an ad hoc network.
Click to open Network and Sharing Center.
Click Set up a new connection or network.
Click Set up a wireless ad hoc (computer-to-computer) network, click Next, and then follow the steps in the wizard.
If one or more of the networked computers is joined to a domain, each person using the network will need to have a user account on that computer to see and access shared items on it.
If the networked computers aren't joined to a domain, but you want to require people to have a user account on your computer to access shared items, turn on password-protected sharing in Advanced sharing settings.
To turn on password protected sharing
Click to open Advanced sharing settings.
Click the chevron to expand the current network profile.
If password-protected sharing is off, click Turn on password protected sharing, and then click Save changes. If you are prompted for an administrator password or confirmation, type the password or provide confirmation.
An ad hoc network is automatically deleted after all users disconnect from the network or when the person who set up the network disconnects and goes out of range of the other users of the network, unless you choose to make it a permanent network when you create it.
If you share your Internet connection, Internet connection sharing (ICS) will be disabled if you disconnect from the ad hoc network, you create a new ad hoc network without disconnecting from the old ad hoc network for which you enabled ICS, or you log off and then log back on (without disconnecting from the ad hoc network).
If you set up an ad hoc network and share your Internet connection, and then someone logs on to the same computer by using Fast User Switching, the Internet connection will still be shared, even if you didn't intend to share it with that person.