I have had the same problem more than once. Here are things I did to help relieve the text-based dashboard or the completely inaccessible dashboard and get back to the graphical UI. These are more-or-less in order of complexity:
Reboot your computer
Clear the cache on your web browser. This will lose any saved passwords, so make sure you have them written down.
Clear the cache the WordPress server. This can be done from the text version of the Dashboard under “Flush cache.”
Reboot your cable modem
Reboot your router
Warning: I am suggesting rebooting the router, NOT resetting the router. If you reset your router, you will lose any customized settings unless you saved them. Rebooting a home cable modem and router can be done if you know the IP address and login credentials. Otherwise you will have to power cycle them with a switch or physical unplugging/replugging.
Deactivating plug-ins (through the text UI) is also a possible cure which has been suggested to me, but I have found the steps above to be more effective.