pro-sites and blog templates acting weird?

Please advise as I would anticipate this is a common issue?
What do i need to do to trouble shoot and can you give me advise as to how to fix...

Each time i try and create a new site it says -

Already Installed

You appear to have already installed WordPress. To reinstall please clear your old database tables first.

And seems the site created takes on a new domain like egfdgfgdh crazy letters... Long story short try it ...