My girlfriend's mom crashed their 2001 mercury sable, but their other 1997 mercury sable is having starting trouble.

It never starts when they want it to. When her mom was driving it, she would wait 20 minutes between attempts to start it and it usually would. One day, she was stuck for an hour and a half in the parking lot, and with it being so cold out there, that's not an option anymore.

The lights come on, the radio would work if if you turn it on and the doorbell chimes with the keys in the ignition. Jumpstarting it has only helped the situation once.

Her cousin replaced the battery. Her uncle replaced the fuel pump and changed the oil (?). They cleaned the engine to see if brake fluid was the culprit for the electrical trouble.

Nothing's working, but I think it's either the solenoid or the starter (I think they actually come in the same package, no? Only on older vehicles were they separate).

Any other insight?