After fully playing SSF4 for the first time, i realized there was some strange issue with my D-Pad. I literally couldnt do any Special's that involved the Down or Left buttons. The game would detect Down and Left, but no Diagnal. (Though, i could do it back to back on the Analog Nub with no problem). After getting my new one, the D-Pad seemed much more firm (The pad on my first one seemed to wiggle around). Not sure if its an isolated incident or something, but might be worth checking with your's to see.