Why did my SSH button stop working?

Background Information

When you launch an EC2 instance, it is configured with a default password (Windows) or trusted SSH key (Linux).

Answer 

If someone goes into the instance and changes the password (Windows) or the trusted key (Linux), there is no way for the RightScale Dashboard to know about the change.  Hence, the RDP/SSH buttons will stop working.  So, if you change the password or trusted key, make sure you know:

1. the new password or public key
2. how to get into the instance yourself (that is, outside of using the Dashboard)