So how does burning a body stop a ghost?

[Smith Dr John Smith]

Any ideas?  I mean the person is already dead and her body should have decade by this point.  I mean if your ghost needs your body what good is it?

[Darth Geek]

I thought it was particularly funny seeing as the apparent origin of the ghost was that somebody stole here beloved creepy doll and that was supposedly a huge "disrespect" to her dead body. So to solve this desecration, you light her up like a redneck BBQ?!

[Compound]

Because in tradition destroying the body will often stop a spirit. Some spirits are bound to the material world because of something left undone and others are tethered here by their remains. In the first case, those spirits are able to move on by resolving what is undone, and in the latter case, if their spirit doesn't have an anchor to the material world it can't return here.

If you look at traditional methods of dealing with evil creatures, "getting rid of the bodies" pops up a lot. (That and burying at crossroads.) And, as a side note, if you ever watch "Supernatural", they also use the "Ghost problem? Find and burn the remains" method, so it's not unique to this film.

[LuvBJones]

But the original ghost that killed the little girl, the girl's parents, and their cat, was never destroyed! They torched the little girl, thus eliminating the immediate haunting, but the original ghost still inhabited the creepy clown doll, thus causing Ham Man to become intimately acquainted with the downtown express. We've still got one more body to exhume and set fire to. SEQUEL, BABY!!