Everytime I click on the timeline to go into another frame, or click the ffwd or rewind button, the model deforms itself in some demented way.

It's not like I set a frame by accidently while modelling because:

A: once it's happened you can hit play and the timeline cursor just loops over with no events on screen

B:Once it has deformed you can't 'undo'. What happens is it undoes eveything u've been working on b4 the 'accidental disfigure' yet it remains disfigured in the same general way, as though it had been like that the whole time.

I have considered that maybe this is in connection with, say; previous polygonal modelling whilst the object was in a different location entirely.

One example is a character i've been trying to animate, when it disfigures, the head comes off, stretches the neck and the head stops roughly in the area I was working on it, before I attached it to the body.
Whereas on the other hand, a part of another model i've been doing has had a part dettach itself and go off to a nearby but random location on the 3D grid.

I was wondering if anyone could help me out with this issue...
I have the feeling it's because one of the thousands of features in maya is activated somewhere...

I look forward to hearing from anyone who knows what the cause is

Thanx for your time

Sean