New
#21
If you just want to extend the lifetime of your existing Windows 10 installation, one that began life with a technology preview license that time-bombs in January 2016, all you have to do is buy a retail version of Windows 10 either from a store or directly from Microsoft online. You will receive a retail package activation key with your receipt. Replace the technology preview key with the retail key you just bought using slmgr (someone else will have to give you the correct option, I don't want to guess).
You will not have to reinstall Windows 10, nor will you have to reinstall any of your applications. Given the correct key, Microsoft's activation server will see your installation as a retail package and activate it accordingly. This is the only option available to you that does not involve upgrading your existing Windows 7 installation.