Installing a program/software

I am trying to Install a software but its gives me an error stating that “uninstall any previous version of this program before installing this” and terminat/stop the instalation. this software is not currently installed on my system. i installed that program once and after using it i uninstalled it with add/remove program. i am not finding any componant of that program right now in my system. pls tell me from where i can remove its components & can install the new version.