have something called 'Connection Manager' that would help you crate many profiles and save the passwords of those wireless networks so whenever you go, you have to just pick up that profile and you are already connected.

It will take over your windows wireless zero configuration and sometimes it might even stop it. You have to make sure that this services is still running and that your wireless connection properties had the 'use windows to configure my wireless network settings' checked.

Someone in our office had this issue and i can see that he was feeling bad about it, but problem was fixed :)

To make sure that the mentioned service is running:
Start--> Run --> type there this phrase without the quotes 'services.msc' and from there look for this service 'wireless zero configuration' and make sure that it's set to 'Startup Type:Automatic' & 'Status:Started'.

If you have windows vista, renewing the connection would do. Either right click on the connection and choose 'repair' or go to the:
Start --> Run --> type there 'cmd' without the quotes and a black screen should appear.
Type there:
ipconfig /release [there is a space between ipconfig and /release]

Best Regards

Do not dwell in the past, do not dream of the future, concentrate the mind on the present moment. (Gautama Buddha)