Are My Backup Files Safe from Malware?

If you back up the files containing the virus, then they would certainly be infected as well. I recommend utilizing "cold" storage methods to avoid accidentally selecting the wrong drive during the process.

If your files are infected, then yes, they could carry the malware with them. Sometimes malware can also replicate itself when you plug in a USB drive. In the past, when I faced this, I connected my hard drive to another computer that had a good antivirus installed. I scanned and cleaned it before making a backup.

These days, modern malware isn't primarily spread via file infections, so the likelihood is lower, but it’s still possible. Just to be safe, ensure that you do a fresh install of Windows, keep it updated with all the patches, and run a scan on your backup before restoring.

There's a chance that your files could be infected. It's a good idea to scan them before restoring.