Microsoft SQL Server Questions

I am not a pro on programming, but here is my question as a consumer who has outsourced this area of work at my company.

I have a software suite (for accounting and inventory systems powered by MS SQL Server) at my firm which I have bought from a local company who takes care of everything.

One of my small branch that I just opened had a windows XP system as server. (this is the only computer there as the store is very small). There is some virus on the system level that the programmer cannot treat or any of the other guys that I have tried. When I told the programmer to format and reinstall his program and everything. He told me he would charge me extra as he will have to repurchase the SQL server license.

What I want to ask is, will the last license he purchased (less than a year ago) work, am I getting ripped off?

Or is he correct in purchasing a new license?