I realize this is an older thread, but wanted to share in case others encounter this problem as I recently did. This is for a (Toshiba Satelittle C850 with Windows 8.1.)
Go to Control Panel.
Under "Network and Internet," click "View Network Status and Tasks."
In the upper left corner, you'll see an option to "Change Adapter Settings."
Find the "Wifi" icon, right click, and select "enable wifi."
This is pending the wifi connection is working properly, but your toshiba is not showing any networks. I'm not sure how mine got turned off, but this did the trick.