Can I Install a DotNetNuke in my Root Folder

Yes, you can install DotNetNuke 4.9 release to your hosting account root path (if hosted with Godaddy, maybe even with all shared hosting providers) with reading following tutorial.

How to Install DotNetNuke to Root Path of Your Hosting Account

I just updated my old tutorial and changed instructions for latest release of DotNetNuke and Godaddy Control Panel (Hosting Center).

I'm also going to update other Subscriber Tutorials. Keep an eye at this blog :)