OK, you've proven that the firewall is not the problem. The error message is pointing to something related to the wireless NIC.

This could be driver related (false positive in the AV product deleting an important file?), the antenna may have become disconnected (assuming it has an external one), the NIC itself may have failed (unlikely, but not impossible), NIC not scanning the channel in use by the Access Point (does the driver allow you to specify channels in use?)

Given this problem seemed to start when Avast was installed I would definitely look for a software cause. Perhaps you could reinstall the drivers?


--=-- My credo: If it's worth doing, it's worth overdoing - just ask my missus, she'll tell ya laugh --=--
You're only paranoid if you're wrong!