I had this problem in Windows 7 where wireless device always show disabled.
I opened Control Panel\Network and Internet\Network Connections and then right click on disabled Wireless Network Connection, and choose Enable. After that status window appeared show ‘Enabling..’ message, but the device was still disabled.
To fix this problem, I opened Control Panel\Administrative Tools\Services, and then scrolled down to bottom, I found service name ‘WLANAutoConfig’. The startup type column showed disabled. So I change it to Automatic, and start the service.
After reboot I found my wireless device was working.