The following guide will show you the steps to be able to connect to a wireless network using Windows 7.
The first step is to ensure that the wireless adapter you are using is enabled for use.
To check this right click on the icon circled to the right (located bottom right of screen next to the clock), then select Open Network and Sharing Center.
This will open a new window. Click on change adapter settings to display the network connections your computer has installed.
Navigate to the wireless network card that you will be using to connect to the network with and ensure is it enabled. If the network card is disabled it will be greyed out in the example below Local Area Connection and UK are disabled.
To enable your network card right click on the card you wish to enable and click the first option enable.
To then connect to a wireless network right click the network then click Connect/Disconnect. This will then search for available wireless networks and displays them in a list. Select the network you require and then click connect. If it is a secure network you will be faced with a security key input screen as below.
Enter the correct security key in here for the wireless network and click ok.
You should now be connected to the network.