upgrade from comcast 360

i just bought the retail version of 360 version 5  to get rid of my lame comcast version 4 can i install it over the comcast version

 or do i have to uninstall it first i dont want to lose my password and settings. i never uninstalled any other version before it always did it all by its self with the new version ( comcast will never up grade there version any time this year,cant live with version 4 forever)    many thanks!!!!!!!!!