For the most part, you shouldn’t lose any programs, files, photos or documents when upgrading from Windows 7, Windows 8, or Windows 8.1 to Windows 10. (Still a good idea to back everything up first.)
However there will be a few things that won’t survive the upgrade.
Users of Window 7 Home Premium, Window 7 Professional, Windows 7 Ultimate, Windows 8 Pro with Media Center, and Windows 8.1 Pro who use Media Center will probably be disappointed to see that it is removed.
Windows 7 Desktop Gadgets
Desktop Gadgets will be removed when you install 10.
Windows 7 Games
Solitaire, Minesweeper, and Hearts games that come pre-installed on Windows 7 will be removed. But you can get free versions of Minesweeper and Solitaire for Free in the Windows App Store.
USB Floppy Drive Support
If you’re using an external floppy drive plugged in via USB, it’s not going to work unless you are able to download a driver from the manufacturer’s web site.
Windows Live Essentials One Drive App
If you have the OeDrive app installed as part of Windows Live Essentials, it will be replaced by the integrated version of OneDrive that shows up like another drive on your computer.
Windows 7 DVD Playback
If you want to watch a DVD movie on your computer, you’ll need to install separate playback software.
There’s one more big change coming to Windows 10.
Updates Will Be Automatic
This is part of the push to keep everyone on the same page and part of Microsoft’s desire to do smaller, gradual updates to the operating system.