MSSQL app, converto to mysql (1 reply)

Sorry if this is repost or a lame/stupid question, but i would really like some help/lights on it.
I have an windows application that uses MSSQL, however, with time, and LOTS of data, it's getting slow. Is it possible to "fool" the application? making it believe that is connected to a MSSQL server, but using a MySQL instead?!?!?! (with already converted tables/data/etc...
The need here is to eliminate the windows server+mssql, but we cannot modify the application.

THANKS!!!