the reason why it keeps falling (most likely) is the rings that hold up the carpet are ripped. All you really have to do is buy metal rings and some thick thread. Sew the rings into the proper places on the carpet (there are 4 of them if i recall correctly). after that, all you have to do is take off the black plastic in the back... you will see the four studs sticking up to put the carpet back. By doing this, you will fix the problem permanantly. Replacing the carpet could get you in the same situation anyway, because the design isn't that good.