First, you need to isolate what is really happening here.  Guessing,
and throwing parts at it,  is a losing strategy.

You indicate it will crank over but will not fire.  But, it seems the
battery
is still draining.  Does it drain because you are cranking it, or because
there
is a basic problem here??  Charge it up, clean battery cables and make sure
all connections and grounds are tight and electrically making good
connection.
Make sure there is no parasitic drain on the battery, like a trunk or glove
light
that isnt turning off, etc.

You  need to see if you are getting ignition voltage.
Take off one of the spark plug cables and attach it to an old spark plug,
and lay
the spark plug on a grounded surface under the hood.  Have gf crank again
while
you watch.  Do you have spark?  If not, you must find out why.  Typicals
causes
include bad ignition module, bad coil, bad wires, bad crankshaft sensor,
etc.

Now, with the battery having full charge,  get yourself a can of starting
fluid.
Don't putz around with gasoline.
Have your gf help you.  You read the instructions, and spray
the fluid into the intake while she cranks.  IF it tries to start, you
likely have
a fuel delivery problem.  It could be a bad fuel pump, a plugged fuel
filter,
water in the tank, or other.

The last thing you need to check is compression.  IF the belt or chain has
failed,
then the engine will not start.  But check it before you start trying to
replace a belt.

Let us know what you find, step by step.