Trying to figure out the problem with my sisters car, Checked the fuses, swapped out the efi relay, changed the starter (thought maybe it was a coincidence that it stalled and wouldn't start again), can't figure it out!

Car has fuel and pretty sure it has spark, it seems as if when the starter turns nothing else happens. The starter doesn't even sound normal.

Could a bad alternator do this? Could that be the cause? Cause I can't figure out anything else!

 

I'm not really clear about what your saying.

You replaced the starter, so I assume it was because the old starter wasn't turning the engine over to begin with? Now you replaced it with a new starter.

Does the car crank over now?

Your pretty sure theres fuel and spark, but are you positive?

If the cars turning over (I'm assuming it is because you say it doesn't sound normal)You need 4 things for it to run, spark, fuel, air, and timing. You need to check each of these and find out which is the culprit.