Background: I got a used/refurbished Dell laptop that has 2009 Windows 7 Home Premium SP1 installed. It came with a disc to install 2011 Windows 7 Home Premium SP1 "...for distribution with a refurbished PC."

Question 1: What is the difference between 2009 and 2011 Windows 7 Home Premium SP1?

Question 2: Is it worth the time and effort to install the 2011 edition? (I'm a neophyte that views this task as akin to blindly walking through a minefield.)