Do I need to a driver or library?

Hello All,
Currently I have a windows application that deals with reading and
writing patient information. At this moment each patient has its
individual ascii file and I use the fread and fwrite to read and write
files respectively. After being in existence for 6 years now, I feel
strongly to moving towards a database option where patient information
will reside in a database and reading and writing would be handled by
Insert, Edit & Select statement. Our primary users are pharmacist and
doctors who are not very computer savy.
I am interested in using PostGreSql database. Thus, my question arises,
if I used PostGreSql Database and provide it with my application will
the user need to install any drivers at their end or do I provide
library files along with the application to serve as postgresql engine.
This is my first question on this newsgroup so if I am not explained
the issue properly please let me know.

Regards,