The problem I was facing was the install crashing and not able to finish. Looking I found a blog, the solution that worked for me was :
Disabling "Nested Paging" in Setting->System->Acceleration allows to start the system.
Disabling "Nested Paging" in Setting->System->Acceleration allows to start the system.
Turns out you can edit the physical path of the Default Web Site (right click, Manage Web Site, Advanced Settings). Change that to the physical path of the app you want to be default, make sure other settings match (in my case the App Pool had to be changed), and there you go.Direct link to best reply