I painted my living room with paint that is very old. It now has a bad mildew...

[wnbgto]

...smell. How do I get rid of it? I had one wall that was damage from a leaking roof. After getting the roof repaired, we then had the damage drywall replaced. The insulation was not damaged or wet. The paint I used is about 3 or 4 years old. After painting we noticed a very bad mildew type smell. A friend told me that the smell should go away in a couple of weeks. It's now been almost two months and the room still smells. Is there something I can use or put on the wall to eliminate the oder? I am afraid to repaint with new paint for fear that the new paint will just absorbe the mildew smell and be just as bad.