Obsidian 1.7.7 Wont run on Windows 7, Not Valid Win32 app?

First, search the help docs and this forum. Maybe your question has been answered! The debugging steps can help, too. Still stuck? Delete this line and proceed.

What I’m trying to do

Was referred to Obsidian by others, installed 1.7.7 from the Obsidian site for Windows. Installs fine but when I try to launch the program it gives the error stating that it is not a valid Win32 app.

Things I have tried

I uninstalled, reinstalled with Admin privilege but it still shows same error.
would like to try another version but dont know where to find older versions.

Help appreciated.

and the version you need for Windows 7 is a few posts down.