I had the same problem.  I was installing the new site on an SQL server that already had an installation on the DB.  Where I found it was hanging was when it was trying to create my HOST user (I use a different name than HOST) in the aspnet_Users table.  Because the table already existed (it does not pre-pend the DNN_ or whatever db table prefix you use) on a group of tables starting with aspnet_.

So I thought all was fine but now one of my sites does not have access to the Host menu, even though DNN calls me the SuperUser.  I believe this is a bug, but have not researched it too much yet.  

Any help would be appreciated.  Comments please...I worked on one of the sites quite a bit, and would hate to have to reinstall and redo all my work.

I've been having the same problem with the superuser creation hanging at 90%. I installed DNN7 on Win 7 laptop via Webmatrix2 about a month ago. It ran overnight and never got past the 90%. Restarted and everything seemed fine. I noticed when building my site that it begain to slow down so much that I could barely add content. I thought that maybe it was part of the install glich. Currently installing fresh on a different computer, Win 7 Pro and it has hung at 90% again. Tried the refresh after 40 minutes and it is still hanging. Use the defaults for both installation, no errors or problems until this point. Any help would be appreciated.