"No disks, no delays—and no leaving the house. With Windows Anytime Upgrade, you can upgrade to a more advanced edition of Windows 7—say from Home Premium to Ultimate—in as little as 10 minutes. That way, you get to take advantage of extra features while keeping your current programs, files, and settings intact.
In the past, upgrading Windows could be a bit of a hassle. In Windows 7, the software you need comes preinstalled. You can buy an upgrade key online or from an authorized retail store. Learn more.
Windows Anytime Upgrade is only available for online purchase in Australia, Belgium, Canada, Germany, France, Italy, Japan, the Netherlands, Spain, Sweden, Switzerland, the United Kingdom, and the United States."
For upgrading for example Windows 7 Home Premium you have to go to:
Start--> in search bar enter anytime --->start anytime prog ---> start cdkey generator--->generate cdkey ---> enter CD-Key ---> GREAT SUCCESS