@cahabagirl I went to a workout with my personal trainer yesterday and asked him some of your questions. He said that weight bearing exercises that put weight on your "long bones" as in your legs are good for a diagnosis of osteoporosis. For instance, lying on a bench and using free weights in a chest press wouldn't help because in this case you are working your upper body and not your long bones. A seated leg press on a machine will protect your back and still work your long bones. Another idea is to do squats. You can start with your own body weight but then move on to doing squats with free weights. He said not to do squats with a barbell (long bar with weights) as this puts too much weight on the vertebrae in the wrong places.

Again, he said form is key. So you will want to do your exercises with weights with proper form so you won't injure yourself. A friend or your personal trainer can watch you and over time you will learn to watch yourself in the mirror. That's what I do.

I hope this helps.