I have installed Ubuntu 12.04 on Dell Vostro 1520 Laptop. But found Wifi is hardware locked, though wifi is working perfectly fine with Windows 7 in the same laptop. I tried to upgrade the drivers as mentioned in other posts/forums but could not resolve the issue. I had the similar problem with versions 11.* as well. Last time the Wifi worked with 10.* version. Please help me to get it resolved.