Is it using windows to manage the wireless or the software from the wifi card manufactuere. Someplace there is a checkbox for that and if you let windows manage the connections it does bad things. Microsoft designed windows to be end user proof and it will hop around between multiple wifi connections looking for a better/easier one and as a lot of people have found will hop off of a perfectly working one on to a non working one if the wind blows the right way. If your in an area where there might be multiple wifi access points then windows can hop around or connect to a secure one with the stongest signal and sit there and not be able to do anything.
Whatever model wifi nic is in the laptop should have a driver and utility download. install that driver and utility and tell windows to let the manufactuers software manage the wifi rather than windows, then use the signal strength meter than came with that utility to see if there is a connection and setup your ssid and such within that utility rather than in windows.