Windows 7 Home Premium: Download Link

What is the difference between Windows 7 Home Premium and Professional?

MEMORY Windows 7 Home Premium supports a maximum of 16GB of installed RAM, whereas Windows 7 Pro Professional Key Global 32/64 Bit can address a maximum of 192GB of RAM.  Update: To access more than 3.5GB of RAM, you need the x64 version. All editions of Windows 7 will be available in x86 and x64 versions and will ship with dual media.

Windows 7 Home Premium contains features aimed at the home market segment, such as Windows Media Center, Windows Aero and multi-touch support. It was available in both 32-bit and 64-bit versions.

Windows 7 Professional is targeted towards enthusiasts, small-business users, and schools.[1] It includes all the features of Windows 7 Home Premium, and adds the ability to participate in a Windows Server domain.[1] Additional features include support for up to 192 GB of random-access memory (increased from 16 GB),[13] operating as a Remote Desktop server, location aware printing, backup to a network location, Encrypting File System, Presentation Mode, Software Restriction Policies (but not the extra management features of AppLocker) and Windows XP Mode.[1] It, too, was available in both 32-bit and 64-bit versions.