Freud's theory cannot be proven or disproven.. It's based on the
"unconscious", which by definition, is unmeasurable.. 
But Freud did contribute a great deal in 2 areas, IMHO:
1) The divide of consciousness in 3 parts: Id (impulse), Ego
(Reality) and Superego (Standards).. It's this constant struggle
between these 3 factors that create tensions in all of us.. (can be
tested? nope)..
2) Defense mechanisms.. When one's ego was challenged, he/she might
engage in defense mechanisms to protect one's ego.. Terms such as
denial, displacement, etc etc are all borned out from the Freudian
tradition.. (can be tested? nope again)..
Hence, the constant antagonism between Psychologist and Freud.. If
something cannot be tested, it is not science.. We study out of
interest, but we cannot further the field..
Btw, Freud believe there are 2 things that drives all human beings:
Sex and Death.. Do go read into his theories.. Very very sexual in
nature.. 
