toolkit,sdk,graphic driver installation completally installed as directed but not verified

I have installed cuda toolkit ,cuda sdk and nvidia graphic card driver when i verified it by using
nvcc -v command it was working but so many other problem was there so i installed it again but now even after installation of all the package nvcc -v command is not working.

I think as i installed it again some problem occurred ,even i got a message that a previous version is uninstalling… but it is not properly installed.

anybody tell me general process to uninstall the package(all package was .run i used sh).
if someone famlier with cuda plz solve this issue.

thanx in advance.