Finding studs in ceiling

In getting a room ready to repaint, I decided to remove the wallpaper border that was at the top of the wall by the ceiling . I used sizing under the border before I put it up. When I started removing the border some of the paint pulled off with the paper. The worst happened on the outside walls. It's not just the last applied layer of paint that peeled but goes down to a color I don't recognize as one I painted. This is a house that is 50+ years old. There are a few places where the paint came off below the border but not many. I have a mess! What do I do now in order to get the walls ready for repainting? frustro

I would like to divide up my family/living room because it's just too big and an extra bedroom is always nice. How difficult is it to install walls with a sloped ceiling? Here are pics. I would like to add a wall at the left of the entrance. [IMG]http://img.photobucket.com/albums/v136/skimmilk68/Houses/IMG_4111.jpg[/IMG] [IMG]http://img.photobucket.com/albums/v136/skimmilk68/Houses/IMG_4112.jpg[/IMG] [IMG]http://img.photobucket.com/albums/v136/skimmilk68/Houses/IMG_4113.jpg[/IMG] [IMG]http://img.photobucket.com/albums/v136/skimmilk68/Houses/IMG_4114.jpg[/IMG]