How to Set Up an Ad Hoc Wireless Computer-to-Computer Network
Have you ever needed to create network between two laptops and you did not have a network cable available? As it turns out, you can create an ad hoc network using their wireless networks cards. You can use that network to transfer any kind of files between the two, as if they were on a normal network. If you are curios to learn how it works and how it can be done in Windows 7, don't hesitate to read this tutorial. The guide will be split into three parts: creating the ad hoc wireless network, connecting other computers to it, and sharing files & folders on the newly created network.
NOTE: Before following any of these steps, make sure wireless is turned on, on the computers between which you are about to create the ad-hoc network.
Step 1: Creating the Ad Hoc Wireless Network
First, open the Network and Sharing Center . Click on 'Set up a new connection or network'.
The 'Set Up a Connection or Network' wizard will now start. With it, you can configure all types of connections, from a normal network to a VPN connection to your company network or an ad hoc (computer-to-computer) network. From the list of choices, select 'Set up a wireless ad hoc (computer-to-computer) network', and click Next.
You will see a new window which describes the things you can do on a wireless ad hoc network. Read the contents of the window and click Next.
Now it is time to set up the network. First, type the network name and then select the security type you want to use. For more security, I recommend you choose WPA2-Personal. It provides better encryption and it is much harder to crack than WEP. Then, type the password you want to use and, in case you want to use this network on other occasions, check the box that says 'Save this network'. When done, click Next.
The wizard will now create the network. This activity should take no more than a few seconds.
When finished, you will receive a notification that the network has been created and it is ready to use. Make sure you don't forget the password and then click on Close.
Your laptop will now broadcast this newly created network and it will wait for other computers to connect.
Step 2: Connecting Other Computers to the Network
Now it is time to connect other computers to this network. On the client computer, click the network icon from the notification area  and you will see the list of available networks. Select the ad hoc network which you just created and click on Connect.
You will be asked to type the password. When done, click on OK.
Windows 7 will now take a few seconds to connect to the network.
When done, the window shown above will be gone and you can now start using the network.
Step 3: Sharing Files & Folders on the Network
After setting up an ad hoc computer-to-computer network and connecting all client computers, one would assume that features such as file sharing, networking discovery, etc. will be working and you would be able to start sharing the content you need. Unfortunately this is not the case.
After a client is connected, it will spend a few seconds identifying the network. When this happens, the Network and Sharing Center  will look similar to the screenshot below.
After the network is identified, Windows 7 will assign to it the public network profile . This means that you cannot share anything. Another problem is the fact that you cannot change the assigned network profile  from public to work or home.
This means that you have to manually change the network and sharing settings for the public network profile. To learn how to do this, check out our tutorial on How to Customize Network Sharing Settings in Windows 7 . Make sure you turn on all the features you need for the public network profile on all computers which are part of your network.
SECURITY WARNING: when you disconnect from the ad hoc network, make sure you reset the network sharing settings for the public network profile. If you keep them unchanged, the next time you connect to a different public network, your computer might be at risk by allowing others to have access to your files and folders. So, make sure you reset these settings to their default values when you are done.
This feature can be useful when you need to connect your laptop with another person's to quickly share some files. With further configuration you can also use this type of network connection to share the internet connection on one of the computers.
The not so fortunate part is that it seems impossible to easily change the network profile assigned to this type of connection. In most cases it will be stuck to public and you will need to manually change the network sharing settings of the public network profile. This, as mentioned above, can lead to security problems in case you connect to other truly public networks.
If you know a solution to this problem or you have some other interesting tips to share, don't hesitate to leave a comment.