Try to get the roof to slide back 3-4 inches, the whole sunroof.
You can then pull down on the front part of the sunrrof headliner panel, it clips to the front of the sunroof panel, then the headliner panel can be slid back so you can put new screws in. You can have a look-see for the old screws, don't think you'll see them.
You may have to manually help the sunroof slide back those first 3-4 inches. The bar that goes acroos that the cable hooks to is called the bridge. It may be broken, you'll be the first to know.