Hi Gini, I've been doing the same thing. Those nails in carpet strips seem to hold better than any nail I've run accross. The first thing I had to realize was that that nail has already damaged the floor, AND It's just far enough out so the quarter round won't hide it. I sharpened one of those pry bars (about one and half ft. long) on the inside of the curved end (not the right angle end). Then I put about four layers of duct tape starting about two inches up from the sharpened curved end (on the outside of the curve) to protect the floor. Then I used the hammer to get under them. I think these strips were made by the devil. Getting rid of them after you get them out is a pain too. The advantage I have is that we are going to re-finish the floors so the pry bar damage is nothing compared to the nail holes. I don't know what type of flooring you have but we have narrow and thin maple that tends to come up, sometimes, when we're prying. When that happens I use another pry bar. Good luck, I hope you don't have to much of it.