Personally I'd get a cheaper case and stretch to a sandy bridge cpu. $150 should get you a decent 1155 sli mobo and if you get a $60 case its an extra $45 towards a better cpu.
You'll have far better upgrade options and better gaming performance.
About the harddrive with the OS, it would be best to do a complete re-installation of the OS. As there will be a lot of rubbish left over from the last installation (drivers, registry settings, etc).
Im sure he just said hes not getting an intel cpu!
Anyway buddy, pretty solid build just 2 things i would swap out are..
Ditch FX4100 and buy a 960T, true AMD quad core which can be OCd to 4ghz on air cooler.http://www.newegg.com/Product/Product.aspx?Item=N82E16819103995
Ditch the 550ti and buy an AMD 6870http://www.newegg.com/Product/Product.aspx?Item=N82E16814161389
OH and buy a decent aftermarket CPU cooler such as the Hyper 212 Evohttp://www.newegg.com/Product/Product.aspx?Item=N82E16835103065