My mother's garage door is not working properly. The door opens and closes with the wall button, but the remote only works from inside the garage. She bought a new remote and it still doesn't work. Can anyone please help me figure out what is wrong?

Did she buy an OEM remote, identical to the one that came with her opener? Any chance the dip switches on the remote or the receiver could have been changed? My wife dropped her remote and one dip switch did change.

Good points from ballen... However, if the opener uses a rolling security code it won't have any dip switches. The fact that the remote works, but only from inside the gargage, tells me the opener is receiving a signal. Check the opener/motor unit and see if the antenna is fully extended and not broken or missing. The antenna is usually a flexible wire, and even though it may still be attached, it could be broken at the base and not pick up distant signals. Was any work recently done, such as a new garage door, wall insulation, etc?