Toad for Oracle version 11.6.0.43 is dead slow

It looks like Oracle is done executing the query (otherwise the execution time would be bigger) and Toad is hung on something (hence the "not responding").

I'm not sure what's going on, but resetting your user files may help.

You can try to reset your user files. Michael describes how to do that in this thread, and how you can restore some of your options afterwards.