A virus is a malicious program that installs on a user's computer with the intent of spreading, stealing or simply causing havoc in the environment in which it resides. While it may be a stretch to call Windows 10 a virus, it isn't the longest journey I've taken. It pops up asking to be installed for free, and once installed it can slow things down or at the least promoted features stop working altogether. If you have a new PC, Windows 10 will probably run just fine, and you might even like it. However, if it does not, here are steps for rolling back to your previous version of Windows:

Open the Start menu and select Settings. Click the "Update & security” icon and select “Recovery.” Select the “Go back to Windows 7” or “Go back to Windows 8.1” option depending on your version. Click the Get started button to remove the Windows 10 installation. 

PS, If you're missing the days of your Windows 7 menu bar, click below to download it and enjoy the simpler menu again:
Classic Windows 7 Menu Download