To migrate a DotNetNuke site to another windows server you need to move both the database and the site to the new server.
You need to update your web.config file so that the database connection string points to your new database.
There are two tags on database connection. You have two look on these tags :
<connectionStrings>
<appSettings>
Migrate to another domain name
Perhaps you also want to change the name of the site: for example, your installation of DNN is made for the site www.mysite.com but you want to move everything to blog.mysite.com.
You have to go to the DNN database and edit the table PortalAlias
(right click on PortalAlias then click “Edit Rows”).
You must add a new line in the table with the value of the new site name.
Click on the last row. Leave the first column default.
Second column is your portal number (default is 0).
In the third column enter your temporary URL ( blog.mysite.com).
Set the last column value of the new row as “True” and change the other to “False”.
After this, very important, you have to go to IIS, in the Application Pool section, right click on the application pool of your site and click on “Recycle”.