Deb,
About your "screamin knees"...first of all you need to find out whats wrong with them! If it's osteao-arthritis or purely from being overweight then Curves could work for you. I have quite a few women with knee problems and if they can't use a certain peice of equiptment, we make modifications so they can continue through the circuit. You may have to start out with a small range of motion on the ones that use your knees, but because its all hydrolics you can't over-do it.
Hopefully, you will find a good Curves in your area. Because it's a franchise we are all "supposed" to be run the same way.

If you call to make an appt. (Its no obligation, just lets you try the machines and talk with staff so you can see if it's a good fit for you) tell them you talked with an owner from MI and she said they should be able to work with you.
Having said all that, EVEN if you have to skip a couple machines, as long as you work hard on the others, you will see results and as you lose your knees should get better!