One of the problems of buying a new PC is that it typically comes loaded with junkware—usually trial or limited pieces of software that you don't want or don't need. And that software can slow down your computer and chew up memory.
You can try to uninstall each piece of junkware to clean up your PC. But that takes time and can still leave files, Registry entries, and other unwanted stuff behind. Instead, you can return your Windows 10 computer to a pristine state via a free software tool offered by Microsoft.
Microsoft's Refresh Windows tool purges all applications that don't come built into Windows 10 by installing a fresh copy of the operating system. That includes all third-party software, including unwanted junkware. It also includes software you may want to keep, such as Microsoft Office, so you'll need to make sure you have the necessary media to reinstall such programs. Further, your Windows settings are reset to their default options. Finally, the tool can keep your documents and other personal files intact or remove them completely.
To access this tool in Windows 10, click on the Start button > Settings > the category for Update & security. From the Update & security window, click on the setting in the left pane for Recovery. Then click on the link in the right pane under "More recovery options" that reads: Learn how to start fresh with a clean installation of Windows.
Resource : http://www.pcmag.com/news/348679/how-clean-up-windows-10-with-the-refresh-windows-tool