Hi, Betty Ruth. First, a suggestion. When you put a post on one subject in the middle of posts on another subject, not as many people read it. If you start yourown subject or thread, more people look at it and you have a better chance of getting an answer. And with your arthritus, you probably don't want to type any more than necessary for the results you want.
I haven't hung a suspended ceiling but have put in a couple of basement ceilings using tile stapled to 1x2's nailed the joists. With these, I had to box in the window opening first and you will probably have to do something similar. Looking at the problem and thinking about it will probably give you some ideas since the framing around the window opening may be different than the framing around mine also. I will say that the moldings hide a lot of sins in my installation.