how to clear add/remove program contents

i am working in an organization.all OSs are win98. in our organozation all registerd s/w are using. some unlicensed s/w are also there.users are deleated that path from program files .At the time of i am trying to uninstall thet s/w that is not supporting.In ASSET TRAKER showing that s/w but physically that is not working.how to remove that content from ADD/REMOVE programs