On some IBM or Lenovo ThinkPad models, such as ThinkPad T410 and T510, the wireless LAN or Wi-Fi radio can turn off or disable randomly. By default, Access Connections of ThinkPad may turn off the wireless LAN network adapter card when it’s not in used, inactive or not connected to any access point.
However, in this case, the problem stays with wireless radio indicator light off, where user cannot turn on and enable the wireless LAN radio via software attempt by pressing Fn+F5 keys, despite the hardware switch button (if any) has been set or slide to ON position. In “Wireless Radio” dialog, the 802.11 Wireless Radio status is always off, no matter how many times user presses on Power On button. Even repetitive turning on and off the wireless radio does not help to enable the wireless.
When the above issue happens, the only way to get back the wireless radio signal working is by restarting or rebooting the PC.
The issue appears to be caused by incompatible or conflict wireless adapter or WiFi card driver, especially for Intel driver software.
To resolve and fix the wireless radio been software-control turned off or disabled randomly, try to uninstall Intel(R) PROSet/Wireless WiFi Software. Use only the Lenovo/IBM provided drivers for the wireless network adapter.