If you are considering a Windows 7 upgrade, read this free lesson first to understand how to upgrade successfully.
If you are currently using Windows Vista, your upgrade experience should be easy. If you have XP, upgrading will likely be more complicated. Either way, it is probably best to download and run the Windows Upgrade Advisor before proceeding.
Based on the current version of your operating system, you will need to figure out if you have to perform a simple upgrade or a custom (clean) installation. You can visit Microsoft's Upgrade to Windows 7 page to determine which type of upgrade you need and what additional information should be considered before performing the upgrade.
Even if you do not need to do the custom (clean) installation, it is a good idea to back up your files before upgrading. For more information, read Protecting Your Computer in our Computer Basics tutorial.
Microsoft provides instructions for doing a custom (clean) installation. However, you may want to consider using a computer service professional if you are not comfortable with this process.
Once you have determined which Windows 7 version you want and what kind of upgrade you need to perform, you can go to a retail outlet or visit the Microsoft Store online to purchase your upgrade.