'96 Buick Skylark, wont turn over.

We just got back from vacation (gone for almost a week) and before
cranking the car that had been sitting there for nearly a week I decided to
get some oil and add it into the top of the engine to help it with the turning
process. I get in the car everything comes on the dash just fine, turn the key
and the starter cranks, but nothing happens (the starter does sound a little
different than normal more grindy). I have had no issues with the starter up
until this point.