wont start

I recently purchased a oldsmobile 88...a couple of weeks ago it was cranking and working but now it just makes this clicking noise when i try to start it....i thought it may have been the battery so i purchased a new one...when no response thought it may have been the starter so I took it off and took it to be tested and they said the starter is fine....a month or so ago the harmonic balance was replaced....so now i am wondering why the vehicle will not start to anyone have any suggestions