Hey everyone. I just purchased a house and have embarked on my first painting project. We bought a two family and live on the 2nd and 3rd floors- our bedroom is in the "finished" attic. I wanted to repaint it so I started pulling off the wallpaper to see what was underneath. Luckily (?!?) it practically fell off. Underneath, it looked like plaster- I know it's NOT drywall. Then, as I was pulling off one section, more than I bargained for came loose. It looks like the people before me had painted/primed/ or plastered over some other wallpaper. Underneath THAT layer is some green stuff that my friend the mechanical engineer thinks is fiberboard- MDF, but after reading some forums I guess it could be greenboard. I stuck a nail in there and pulled out a chunk and under the green covering it looks like very soft concrete with hair in it. Yes- hair. Now- the question: I went out and bought joint compund and plaster,. Can I repair the cracks with this? Also- will primer take care of the roughness/bumpines of the MDF/greenbord? Should I tear off the entire layer of stuff under the wallpaper, or just plaster/use joint compound over the green spots? Not all of it is loose. Jeez, I just want to paint the stupid walls... I know, I know, welcome to the world of homeownership. I will do nothing further than pulling off the first layer of wallpaper until I get advice. Supplies I have: Plaster, joint compount, wallpaper remover, that chemical cleaning stuff for wall paper glue and dirt, 150 grit sandpaper, putty knife, plaster-applying flat thingy, a home-repair book, and a migrane.