Hello. I am building a new computer and have a question regarding which operating system version I should buy. Currently looking into Windows 7 over 8 due to the accessibility issues I've been reading about with Windows 8. My question is regarding which type is ideal, Windows 7 Home Premium which is on Amazon for $169.99 or the Windows 7 Home Premium SP1 64bit (Full) System Builder DVD 1 Pack which is on Amazon for only $91.99. What is the difference and which should I buy? The system is being built for playing games mainly, fairly mid-tier nothing too fancy, just the first computer I have ever built and have no idea which OS version is best and concerned about the difference in prices.