The built in wireless card on my T250 just stopped working.  On Device Manager, the network adapter “Microsoft Tun Miniport Adaptor #2” has a yellow exclamation.  It won’t uninstall - says it’s required to boot windows.  I found something on the web that described deleting registry keys.  When I tried it, the reg entries in the T250 are different, so it didn’t work.  Any suggestions?