Hmm, at bootup does the light on the floppy drive turn on? and maybe make a noise? This would tell you its operational. As of wheny uo put a disk in and ask it to load, does it make noises? or just stands there?
Open the PC up, and make sure all cables are in properly for it, and going into the motherboard.
By the way, when did it stop working? Or have you just inserted the Floppy Disc Drive?
I hope this helps