MacBook For Dummies, 6th Edition, Bonus Chapter
Running Windows on your MacBook – using either Boot Camp or a Windows virtual machine – does open a door for Windows viruses and spyware, and you need to protect your system from these insidious outsiders.
If you’ve never installed an antivirus or antispyware application under Windows, take heart: two of the best options are free! You should definitely try Avast Free Antivirus for robust protection against viral attack, and Malwarebytes Anti-Malware is a great tool for identifying and removing the spyware that seems to be everywhere these days.
And yes, it is very important that you back up often . . . this means your Windows system! Use the built-in Backup and Restore system within Windows 7, 8, 8.1 and 10 to create a comprehensive backup schedule, and stick to it. (Note that OS X El Capitan’s Time Machine feature will not back up your Boot Camp partition, so you must back up from within Windows.)