I used my software for syncing pictures...?

...to sync pictures to my cousin's MP3 player. The software was meant for my MP3 player. After I did that, I couldn't use that same software for my MP3 player(to sync videos and photos). Could that have messed with my MP3 player? Now I can't even sync music from WMP 11. The only thing I can do is sync books from Audible Manager. Damn, this sucks! Your help is appreciated. (I've tried re-installing the picture and video converter but it still isn't working.)