We currently have two contact databases in ACT. One of them is growing exponentially and at 70,000 records we are already experiencing problems. We are considering switching to MS SQL because it is already installed on our server. But I do not know anything about how it works.
Is it the back-end of an Access database? A standalone product? Where can I obtain the knowledge and information I need?
You must get training or hire someone who has SQL Server to run the database.
SQL Server is not the back-end of an Access database. SQL Server can be standalone, but that flies in the face of data sharing, the number-one reason to have a database! More typically, SQL Server is installed on a network on Microsoft NT Server, and hosts many databases simultaneously.
Depending on the amount of time available for training, you should either start the Microsoft certification process or start shopping for a candidate who already has experience and certification to help you out.