Painting - Ceiling paint falling down

I've always had problems with paint the wall and ceiling in my house (especially the ceiling) for the past 20 years. It seems that the original paint must have been a poor quality or the drywall damp when it was applied because it's not adhered well. When I try to paint over it with a quality paint the previous layers often peel off as I'm rolling the new paint on right down to the bare wallboard. A paint store manager told me to paint the ceiling with a fast drying oil based primer and then ceiling paint over the old paint. This seemed to work for several days but now the layers of paint are coming down in sheets. I tried scraping all the paint layers off of the ceiling, however, I couldn't get the paint off over areas that had been taped or spackeled. I just redecorated and have new carpeting. Help, what can I do? Can you suggest anything other than putting new sheetrock up? Any suggestions as towhat I can put over the sheetrock or how I can get all the layers of paint off. It's slightly textured. If I could get all the paint off I could reprime and paint. Thanks.