software update

hey, so i got the notification saying that i needed to update my software on my macbook in the app store. every time i go and click "update" it shows the waiting sign beside it but never actually loads or downloads anything, it just remains saying waiting. i've been waiting for over a week for it to update and nothing is working. it won't let me shut my laptop down because it says it needs to finish updating software. it is getting to the point where it is extremely frustrating. please help!