I don't understand "My database is SQL server as both database and web server"
I recommend that you follow the installation instructions at https://dnncommunity.org/documentation.
If you are looking for a painless DNN installation, use nvQuickSite. You'll find it on GitHub. A few mouse clicks will do the whole thing.
Also, I assume you have a reason for installing DNN 7. That one is at least 5 years old.The current version is 9.6.1 and is a much better and more secure version of DNN.