Is Windows 7 safe to use? No. Next question? Alright, I guess I need to explain why, without being so dismissive.
Support for Windows 7 ended in January 2020, which means there have been no new security updates for Windows since. That means Windows 7 isn’t safe to use, even with a firewall and antivirus.
Why Windows 7 is no longer safe to use

Microsoft generally supports operating systems with bugfixes and new feature updates for about five years. After that point in time, they cut back to the minimum, providing just security updates for another 5 years or so.
Windows 7 proved to be one of the most beloved Windows releases ever, and some diehards hung onto it until the very end. But absent the monthly security updates that cause your computer to reboot in the middle of the month every month, Windows 7 isn’t safe to use. Most bugs discovered in Windows since January 2020 are present in Windows 7 as well as in Windows 10, but while Windows 10 got the update, Windows 7 didn’t.
If a really devastating security flaw is discovered, Microsoft may release a fix for Windows 7 to keep that bug from burning the world down. But the majority of security flaws will remain unfixed, and applying the fix for that single update does nothing about the others.
If you have a Windows 7 computer with software on it that you need, and that software won’t run under Windows 10, unplug the computer from the Internet when you use it.
What about antivirus and firewalls? Don’t they make Windows safe?
Your antivirus and firewall software provide necessary security, but they aren’t invincible. If you’ve ever had to take security awareness training at work, say, the infamous Kevin Mitnick Security Awareness Training, everything he demonstrates is on machines with a functioning firewall and up-to-date antivirus. Sometimes he’ll demonstrate ways to hack systems that are fully up to date as well. But a system that’s fully up to date is much more difficult to hack than a system that hasn’t received any updates for months or years.
What about businesses, government and military?
Microsoft offers Extended Security Updates for business and government use. For a fee, which increases every year, Microsoft continues to provide updates the same way they did between 2015 and 2020. The fee encourages businesses to move to Windows 10, which doesn’t require paid support for updates.
The government and military generally do a much better job of upgrading to new Windows versions than commercial businesses do. Generally the government starts its migrations within a couple of years of the new Windows release. When I was a government contractor, I had Vista and Windows 7 on my desk. When I went back into the private sector in 2013, they handed me a laptop with XP on it.
Yes, you’ll hear stories about the Navy using ancient Windows versions, and certain outlets will point to that as yet another example of government incompetence. The Navy refurbishes its ships on a 20-year lifecycle. That includes the computer systems. So that means they have Windows builds on them that are 10 years out of support. Perhaps even a bit longer. The Navy buys extended support from Microsoft to abate this. It always has. That’s part of lifecycle management.
For the rest of us, lifecycle management means upgrading to a Windows 10.
Upgrading to Windows 10
Microsoft no longer offers Windows 10 as an easy, automatic and free upgrade from Windows 7. That said, even today, if you use Windows 10’s USB installer and enter a valid Windows 7 license key when it prompts you, it will accept the key, install, and activate.
Windows 7 admittedly runs better on aged hardware than Windows 10 does, but installing an SSD does a lot to close the difference. Anything with a Core 2 Duo or newer CPU, at least 8 GB of RAM, and an SSD runs Windows 10 more than acceptably. That’s a pretty humble machine these days.