SP 2010 web application fails to start

Question

I removed, then reinstalled SharePoint 2010. Attempting to recover an existing web application, I reconfigured the web application in the new instance, and pointed the existing db to that web application. In IIS, I created a new app pool, together with a new account to run it. In Sql Server, I created a security account for that new app pool account, and assigned it to the relevant database.

I start the app pool in IIS, and it runs. I restart the web application, and that runs, too. I then attempt to access the web app, and the app pool stops. The browser reads "HTTP Error 503. The service is unavailable."

Answer 1

I don't understand why you are creating app pools in IIS. Let SharePoint provision the IIS web site and app pool when you create the web application in SharePoint Central Administration.

Try creating a new web application with a temporary content database and check that you can provision a simple team site. When you have that working you know the IIS setup is okay. Now delete that content database and attach your "old" content database (you may still need to modify the permissions in SQL Server).

If you are not sure about any of those steps the best resource is Technet.