problem in scan now option

i install new version of avast free antivirus.but when i scan any folder it has no confirm in screen that scan is running after sometime its only sound that scan was completed.but which folder is scan and its report is not show.also when i try to install avast internet security , the time to install it is show fair wall driver is not install successfully.after install complete i show in avast (scan now interface ) only icon but not other option to start scan option like quick scan,removal driver scan.how can i solve this.

what antivirus did you have before installing avast?
did you uninstall it before installing avast?
have you run a removal tool to clear any leftover files that may conflict?