Is your "white clamshell laptop" a Classmate E11 with a 250 GB hard drive that you reloaded with this year's image? The WiFi drivers in that image only work with the 160 GB version. FIRST included directions for loading the proper drivers at the end of the
Classmate imaging instructions.
Otherwise, start troubleshooting with the obvious things. Is the laptop's wireless adapter enabled? Is its WiFi radio turned on? Does it see and connect to any other wireless access points?