It can happen that you start having problems with a wireless network which worked well in the past. This might be due to the fact that the its settings may have been changed accidentally or its network profile, as saved on your computer, got corrupted for some reason. In such scenarios it helps to delete the profile of your wireless network and start fresh: have Windows 7 detect it again, introduce your connection details, etc. This tutorial will show how to delete the network profile of a troublesome wireless connection.
Open the Network and Sharing Center in Windows 7. There, on the left side column, click on “Manage wireless networks”.
In the Manage Wireless Networks window, you can see the profiles of all the wireless networks to which you connected to in the past.
Select the network with which you are having trouble, and click Remove.
Confirm that you want to remove the network profile.
The profile of the wireless network is now deleted. Windows will detect that network as if it was a new discovery and you will be able to enter all the details again and connect to it.