2002 Ford Focus initially sluggish & kept dying

Buying the car used I wasn't sure of everything that had been replaced. With the symptoms first we had the catalytic converter removed and it seemed to help with the sluggishness and car stopped dying. After about 3 weeks same problems were happening again. Went simplest route and replaced fuel filter, but also noticed that ignition was getting stiff. When turning key to turn motor over and start you would have to manually turn key back to 'on' position. Anyway, replaced fuel filter, car started fine. Shut it off and restarted another 2 times. After final turn off car would not start, wouldn't even turn over. Just clicked like maybe the starter was bad. Jumped it and it started right up. Pulled cables off, let it run a bit, shut it off and same thing. Dead. Now we replace battery. Does the same thing. In talking to a friend at work about all of it and I keep going back to that ignition being stiff. He suggested that possible the ignition was bad, maybe not disengaging therefore keeping an open current which is draining the battery. Could this be the problem? I need to add, we had battery we replaced tested and it is still a good battery, didn't need to be replaced. This is my daughters car, I'm a single mom and just need some help. I'm learning lots as I go and willing to do the work myself as I can't afford a mechanic. What my friend suggested sounds logical to me. Help :)