I have a ThinkPad T400 and for some reason the wireless capability is turned off sometimes.
When I tried to search for wireless networks, it said that no networks are found even though I turned my wireless adapter on. When diagosed, it says that my wireless capability is turned off.
This happens randomly and I don't know what is wrong,
This article was originally written in 2011 and at the time, most systems were running Windows XP / Vista / Win 7. If you have an older ThinkPad running one of these OS versions and are using access connections, then this article may still help. If you are running Windows 8 or newer, Scenario 2 may help in some cases.
Upgrading to the newest Wifi driver and power managment driver for your system will likely have the most positive results. Over the last 18-24 months there have been multiple Wifi driver updates on many model systems, especially those with Intel wireless cards.
These symptoms may originally and otherwise be caused by a combination of not finding a wifi network to auto connect to, and / or your power management settings.
Resolving Power Management Scenario 1
If you are in in 'Energy Star' mode for instance, if it can't find a wireless network in X amount of time it just turns it off. Setting to "Max performance" or disabling the setting to allow the wireless card to save power.
- Press the blue ThinkVantage key
- From "Resource Center" menu, click "Wireless" and then "Find Wireless Networks".
The Access Connections window will pop up
- Go to "Options" tab and uncheck the "Allow the wireless LAN radio to be turned off when inactive." box
Resolving Power Management Scenario 2
If the steps in scenario 1 above did not resolve the adapter from being powered down during inactive periods and dropping connection, try the following:
Control Panel --> Power Options --> Power Manager (on the left side in red) --> Advanced Settings --> PCI Express --> Link State Power Management. Change both Battery Settings and AC Settings to OFF.
Or more typically...
Control Panel - > Device Manager -> Wifi card -> right click properties -> power tab -> uncheck the box that says "allow windows to manage power to this device"
Resolving Windows / Access Connections Conflicts
You can only have one wireless client software active.
If you want to use Windows to manage wireless, then uninstall Access Connections.
If you want to use Access Connections, don't create wireless connections through Windows, use Access Connections.
When Access Connections attempts to connect, it automatically turns on the wireless radio, while Windows wireless does not.