Windows 7 Professional SP1 32 or 64 bit. Standard Enlish Version, (Additional Language Packs are available via separate download). You'll be sent an Activation Code / License for the OS and an instruction on how to download the Windows 7 Professional and how to active it using the license. This license will work for both 32bit or 64bit machine / OS. Note That, this license is only valid for one single PC. using a single license on multiple PC will void the license agreement with Microsoft. System requirements for Windows 7 (Source Microsoft website www.microsoft.com) The following requirements must be met in order to run Windows 7 on your PC: 1 GHz processor or higher with 32-bit or 32-bit 1 GB RAM (32-bit) or 2 GB RAM (32-bit) 20 GB (32-bit) DirectX 9 graphics device with WDDM 1.0 or higher driver Windows XP Mode requires an additional 1 GB of RAM and 15 GB of additional hard drive space. Method of Delivery: Installation download link for Windows 7 Professional 32/64 bit by email in PDF format License key by e-mail, in PDF format Detailed, easy installation instructions, via e-mail in PDF format