The problem is that your web browser has cached the old log in page for your old firmware. If you delete your cache (temp internet files) that should fix the issue. You might have to manually delete them. If you do not know how then just reset your browser back to default settings. Internet Options-Advanced-Reset... or you could just forget the above fix and use another browser... ;)

First, the upgrade may have replaced the default functionality. Second the wireless signal capacity allowabel for most computers requires letting the system aware of the new setup to share signals. The software is on the computer however requirign to adjust the wireless distribution to accept new codes to retain usual fucntionality.