Windows 7 Ultimate Genuine Version..... 32bit and 64bit....

Windows 7 is the latest version of Microsoft Windows, a series of operating systems
produced by Microsoft for use on personal computers, including home and business
desktops, laptops, tablet PCs and media center PCs.

MINIMUM REQUIREMENTS:
* 1 GHz Processor
* Support For DirectX 9 Graphics Device With 128 MB Of Graphics memory
* 1 GB RAM
* 16 GB Free Hard Disk Space
* DVD Drive

32 bit:
http://msft-dnl.digitalrivercontent.n...

64
bit:
http://msft-dnl.digitalrivercontent.n...