Attention Conservation Notice: Regular readers can skip this post without missing anything of importance.

Solution: I fixed this issue by opening the properties for the network and selecting “do not automatically connect to this network”, then disconnecting, reconnecting, and reauthenticating.

Details: I’m visiting my folks for the weekend, and their ISP here in the Tri-Cities is a little flaky. Earlier today the Internet service cut out and, not needing my machine at the moment, I just put it to sleep.

On resuming the machine, I couldn’t connect to their network. I confirmed that the network and internet were working fine on another machine.

Restarting router and modem did nothing. Restarting the machine did nothing. Restarting just the wireless LAN adapter did nothing. Windows’ Network Troubleshooting Wizard was its typical useless self. I tried reauthenticating to the network and messing with the network settings. Nothing worked.

On a lark I went into the list of visible wireless networks, right click on the appropriate network, selected properties and disabled the checkbox that says “Connect automatically when this network is in range.” I then reconnected to the network, it prompted me for credentials. When I reauthenticated, it worked fine.

I then re-enabled auto-connect and the network continued to work fine.

Seems that flaky Internet plus system suspend somehow equaled corrupted cached credentials or something. At any rate, the secret sauce for me was disabling auto-connect on that network.

Hope this helps.