Please educate me concerning virus possibility

[ConfusedArtist]

Hello, I am wondering: is it possible that a virus or other infection can get onto my PC and remain undetected by my Avast anti-virus (free edition), and then be transferred onto my backup external hard drives when I am conducting a routine backup of files, and then destroy the data on my backup drives? In other words, can a PC infection “remain dormant” and unnoticed by PC security software, and then spring into action later, possibly on a backup drive? Or, am I safe to go ahead and back up my files to my external hard drives once i have done a scan that concludes my PC is currently “uninfected”? Thank you for clarifying!

[Bruce]

of course it’s possible however unlikely to happen to you and that’s why a good backup regimen is to span your backups over multiple sets.
you have to trust your AV though, if you don’t, ditch it.
they are not 100% guaranteed - they cannot be but they are all in the same boat.
they can only look for what they know to look for and therefore are sort of reactive to a certain degree.

it’s all about a layered security approach. and that does NOT mean more than one AV program.
for example, I use Window, MalwareBytes Premium, a modified HOSTS file and uBlock Origin on all my web browsers. and that’ll do for me. you can go overboard and have it rule your life.

why not do a scan of your backups with Windows Defender to get a second opinion.

[ConfusedArtist]

of course it’s possible however unlikely to happen to you and that’s why a good backup regimen is to span your backups over multiple sets.
you have to trust your AV though, if you don’t, ditch it.
they are not 100% guaranteed - they cannot be but they are all in the same boat.
they can only look for what they know to look for and therefore are sort of reactive to a certain degree.

it’s all about a layered security approach. and that does NOT mean more than one AV program.
for example, I use Window, MalwareBytes Premium, a modified HOSTS file and uBlock Origin on all my web browsers. and that’ll do for me. you can go overboard and have it rule your life.

why not do a scan of your backups with Windows Defender to get a second opinion.

I use Avast Free Antivirus and Free Malwarebytes. I am using Windows 7 OS. Too much risk moving to Windows 10, and i don’t want Windows 10 anyway, from what i have seen reported about it (even less privacy, useless apps and ads built into system, slowing the system, possibility of old software malfunctioning, etc). I would like to take this PC off the internet and just get a separate laptop for internet purposes, but money is short and i need a solution for right now.

What is a modified HOSTS file? What is uBlock Origin? I can look them up myself but please let me know how they work for you and why you use them.

Thank you!

[jmarket]

Please, no need to quote previous posts, just adds to clutter.

Too much risk moving to Windows 10,

In fact quite the opposite, Windows 10 is a more secure operating system than the unsupported older Windows 7.

Your best solution, and you say you are using Avast, and do remember no security suite will always catch 100% of malware 100% of the time, is to use another Security app to get a second opinion. Something like Zemana Free, or Malwarebytes ETC, to run ON DEMAND only. Never fall for the trap of running more than one realtime security app at the same time.