is your mobo micro atx, or full atx?
looking at your cabinet, i say the floppy drive bay or top portion of hdd bay will be blocking the gpu.
as i said, CUT IT OFF!!! rip it off with your bare hands for ++MANLINESS++ points. srsly. chicks love that sort of stuff.
no, seriously. who uses dloppy frives anymore? remove those bays. they will be of thin metal in your case. use tin snips (thick metal cutters in shape of scissors) to cut them off.
if you need help, i'll be here. but do post a SIDE shot of your mobo inside your cabinet.