I have a confession to make: I really over loved my Snake Plant. Like REEAAALLLYY over loved it. And by over loved, I mean of course, over watered. : ( If this has happened to you, don't despair! Here is one way to try and save face, along with your rotting plant friend.
Sansevieria trifasciata, a.k.a. Snake Plant or Mother-in-law's-tongue, is an extremely hardy plant. (Which makes it all the more embarrassing to have melted mine.) They are very much like succulents in that they don't require very much water and can handle most environments, with the exception of extreme cold.
When they get really droopy, as mine did - trying to tell me it wasn't happy, it will almost always mean too much water. There are many other factors that go into a healthy Snake Plant, but I'm going to focus on good ol' root rot and how to try and save as much of the plant as possible.