How to redo the gui desktop

[Tom Masterson]

I have a Dell laptop (older).  I have been upgrading it since something 
like Ubuntu 704 so it has been around awhile.  It has developed a problem 
since the upgrade to 11.10.  For some reason it has stopped runnig any of 
the GUIs.  Primarily it seems to be a problem with nautilus blowing up 
regularily.  Is there some way to remove everything and fix this?  I don't 
really want to rebuild everything from scratch as I don't want to remember 
everything I had not to mention figure our where to back up everything so 
I don't loose things like my posfix settings and others I may not remember 
after all this time.

Tom