I used phbb to create an forum years ago. I have the old forum backed up to my domain and got rid of it when I had to change the type of phbb I used. Is there a way I can use phbb to restore it?
In theory if you still have the database, yes.
How do I know if I do? I have a folder with the name forum old, what would be in there that would tell me?
The database would be listed here on your panel: https://panel.dreamhost.com/index.cgi?tree=goodies.mysql&
If you have the old forum folder, there should be a config file that will tell you the name of the database.