Hey, Leo. When I bought this computer, Norton anti-virus came with it. Norton anti-virus is about to expire and I don’t plan to renew it as I’ll switch to Windows Defender since it’s recommended by you and by others. My question: can I activate Windows Defender before Norton anti-virus expires or do I need to uninstall Norton first? Also, should I uninstall Norton after Windows Defender is installed? Finally, how do I activate Windows Defender? I’m running Windows 7, X64, on an HP desktop.
A note on product names: for Windows 7 what you’re really talking about is Microsoft Security Essentials. That’s the old name for “Windows Defender”, which is what you would use if you were running Windows 8. However, for Windows 7 and before, what we’re really talking about here is “Microsoft Security Essentials”.
Typically, the answer to your question is “yes”; you should uninstall the old anti-virus software before installing the new.
Become a Patron of Ask Leo! and go ad-free!
Remember that multiple anti-virus programs can, in fact, come into conflict with each other when they’re installed together.
I recently saw this on a friend’s computer. Basically, his first anti-virus had expired, and he installed another without removing the first. After that, the computer was slow doing just about anything. We also suspected that the problem was causing emails to be lost or incorrectly funneled to spam, or deleted.
The right approach is to uninstall the old, and then install the new. However, this statement assumes that you are handling this in the safest possible way.
Safety through the transition
First, you have to have a firewall in place. Technically, without anti-virus for even a few minutes, you’re somewhat more vulnerable to attack or infection.
It’s probably enough to be behind a router, which acts as a hardware firewall protecting you from the internet. However, if the other machines on your local network aren’t necessarily trustworthy, (i.e., they’re the kids’ machines, or someone you know has bad surfing habits) then you probably want to have your Windows firewall turned on, if it isn’t already, before you uninstall your old anti-virus.
The second assumption is that you actually don’t do anything else between the uninstall and the install. Again, technically, without an anti-virus installed even for a few minutes, you’re somewhat more vulnerable. If you get distracted between the uninstall and the install and you go off and surf the internet, you’re basically vulnerable to whatever you happen to download.
As long as you make sure you do the uninstall followed pretty much immediately by the install while having a firewall in place, you should be okay.
Activation? No need
As for activating Windows Defender/Microsoft Security Essentials, you don’t need to. There is no activation. Once you have it installed, it will start running and it will start doing its job.