My friend has a toshiba satellite L645D-S4040. I reinstalled windows 7 on his laptop but when I tried reinstalling the wifi driver it wouldn't work. I tried the realtek, the broadcom, and the atheros, and uninstalled each before I tried a new one. I even rermoved the wifi card and reinserted it, and that did nothing. I reinstalled Windows 7 again and tried all of the above and still nothing happened. What could be wrong here? thanks!