I found this on
www.arvixe.com and their knowledgebase:
https://support.arvixe.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=56&nav=0,11"
Please use the following connection string and fill in the necessary spots with your database's information:
<add name="LocalSqlServer" connectionString="Data Source=localhost;Initial Catalog=DBNAME;Integrated Security=false;User ID=DBUSERNAME;Password=DBP
ASSWORD" />
DBNAME is what you specified as your database name in the control panel
DBUSERNAME is the username you created to connect to the database (and was associated with the database in the control panel)
DBPASSWORD is the password you associated with the username above
"
You need to change the DBNAME, DBUSERNAME and DBPASSWORD according to their description.
In addition, you need to change the Data Source=localhost, to the server which holds the MSSQL database. This is the server name you use to connect to the database when using e.g. SQL Server Management Studio Express. It might be sql.arvixe.com or something like it. Arvixe suggests either localhost or .\SQLEXPRESS as the data source:
https://support.arvixe.com/index.php?_m=knowledgebase&_a=viewarticle&kbarticleid=68