Wireless network card drivers are what is responsible for the encryption and decryption of the data to and from the network card. When the drivers update or get re-installed, sometimes you cannot connect to the wireless network again.
Some driver updates will mistakenly change or corrupt the settings for the wireless networks (SSIDs) configured on a computer. If the computer suddenly cannot connect to a wireless network anymore after turning on the computer, check the settings for the wireless network before doing anything else, especially if the computer is configured to use automatic updates. There has been no detectable pattern in what can be wrong / changed by driver updates, so check all the settings against the instructions on the WirelessTrakker controller for the computer type and network type.
This is another reason why letting Windows Server Update Services (WSUS) push out driver updates can be a bad thing. If a large batch of computers gets their wireless drivers updated and that update corrupts the settings, there will be a large batch of computers that have to be fixed, one by one.