Unable to Install OS High Sierra

Hi, I have a MacBook Pro running OSX 10.9.5. I never upgraded it from the original computer, but just tried to upgrade to Sierra. I'm able to download the file from the App Store, but when I clicked the install button nothing happens. Now if I go to the app store, it says Sierra is "installed" but nothing happened and I am still running OSX. It no longer gives me the option to download the file. There is no installer file visible either from the download. Any suggestions? Thanks.