Whenever I launch Toad for Oracle or select Session | New Connection, it takes the connection window over a minute to appear. After it appears it works fine and I am able to connect without a problem, it just takes a long time to appear.
Invalid Oracle registry entries.
Click the ellipsis (...) button next to the Connect Using field on the Connection Screen. See if there are any clients that are displayed in red. If there are, remove these clients from the registry.