What does Lady Macbeth's sleep walking indicate about her state of mind?

Lady Macbeth's sleep walking, and what she does and says
while she is walking in her sleep, show that she feel very guilty about all the things
that she has helped to convince her husband to do.

The most
obvious example of this is her compulsive hand washing.  She keeps trying to clean
herself and yet the spot will not come out (since it's only in her mind anyway).  This
shows that she is not able to overcome her guilt.  She feels that her guilt cannot be
washed away.  This is going to lead her to kill herself later on in the
play.