Newegg has the Microsoft Windows 7 Home Premium SP1 64-bit OEM Software for $100 - $20 off with coupon code EMCJNHG253
[Exp 10/25] = $80
with free shipping. OEM version is intended for new systems and cannot be transferred to another computer once it is installed. If you're sitting out Windows 8 - which was actually $70 last week.