su probleme

I have this starnge probleme with the "su" command. Here it goes: I am loged as a user and when I type in my console su. I get this mesage "su: incorect password". It does not let me to type a user or a pass it gest prints out that message. The other programs in Kde I try to run as root show a error mesage. Can anyoane help, Thanks, __________________________________________________ Do You Yahoo!? Yahoo! Movies - coverage of the 74th Academy Awards� http://movies.yahoo.com/