We are new homeowners and very new at home improvement/repair. I am repainting our daughter's bedroom. The walls are drywall. However the window sits in a bit. The sill is made of what looks to be marble. The side jambs however are not. They have been painted many times from the looks of it. The current layer of paint is peeling. It's uneven from so many layers of paint just painted on top of where the previous paint peeled. I'm thinking that I'll definitely have to get a dremmel sander and even things out. My problem is that I don't know how to fix this area after I sand things so that I don't have this problem again when I repaint. Any advice? From the part that I can see where layers have peeled away the deepest I don't even see like a wooden jamb. It's like the wall just stops and juts in to the window. Hope I'm explaining things right. Any help will be greatly appreciated!