Windows 7 support ending soon. What about using a VM to search internet to keep Windows 7 pc secure

That won't keep your windows 7 secure.

You'd be better off installing linux, then putting Windows 7 in the virtual box and create a snapshot that your can always revert to.  That will allow you to undo any malware by resetting Windows back to a "pristine" state.  Only run Windows when you absolutely have to, and don't use any internet connected software.  In fact, turn of networking inside the Windows 7 VM and use the browsers and software in linux and only run Windows specific software in the VM.

If you're a Linux n00b, Ubuntu is likely the easiest to get used to.  It also has the most support in the way of forums and users.  You should have just gotten Windows 10 free when they were offering it for free.  Download the installer back then and save it with the license activation.  That way you would own the copy and you wouldn't be stuck now.

You should probably still convert a couple of you systems to Windows 10, since there will likely be software that you must use that will only run in Windows.  Convert a few at a time at your leisure and don't do it all at once.  You could also buy a new system and update it that way.

In my country, you may buy win10 pro as used license for less than 45 US$, to my surprise even in some supermarkets, so you might want to check out the used software market and regulations in your country.

To your question: if this is about security, all starts with "what do you fear to happen exactly?". Browsing in a VM can overcome a lot of scenarios, but surely not all. So I wouldn't say that your idea is bad, but you have to define what you want to prevent exactly, first.

For secure browsing I use MacOS or iPad and have no problems with most of the malware written for Windows or even Linux.
And there are enough antiviral software tools which can protect your Windows even if MS stops sending its patches. If you follow some rules (dont visit suspicious websites, dont click on suspicious links etc etc) then you can live without any MS update actually.
Take regular backups of your machines and just revert back if  you get some problem. No need to install Linux even.
If you want to use linux for learning and browsing purposes then you can install it as well, I would use either mint or ubuntu. I see absolutely no problem here.

I have 6 computers all networked running Windows 7.   I use Media Center .

In addition to the advice above:

1. Windows 7 has Home Group and you are likely networking using Home Group.  Home Group is gone in newer versions of Windows 10 and you need to use tradition file sharing.

2. No direct replacement for Media Center.  Windows 10 has Photo and Video applications native and additional Store applications.

3. You may be able to do better than $150 per seat for upgrade, but you do need to consider upgrading. Windows 7 is not as secure as Windows 10 and that situation will only get worse as security in Windows 10 improves.

4. Look at the oldest computers as some may need to be replaced.

5. Upgrading old Windows 7 machines to Windows 10 is not guaranteed at all. Best to back up and install Windows 10 fresh. Run the Windows 10 Upgrade Advisor (Microsoft downloads) and see if the computer you wish to upgrade will run Windows 10

An addendum to my suggestion:

If you don't really know Linux, You should just get new systems with Windows 10 and create VMs with Windows 7.  Run everything in Windows 10, and run your Windows 7 in a VM.

If the use of media server is what is holding you back then there are other media servers out there ie. plex or emby..  Personally I prefer plex

Thank you all for taking the time to answer my question.  Thank you for reading my question carefully and supplying such useful answers.

Serialband:  Your suggestion to run Windows 10 as a host and Windows 7 as a guest is an idea I had not considered.  Thank you for the information.  If I can solve the Windows 7 license issue and determine how to install Windows 7 as a guest then this would be a solution.

Mr. Johnson:  I will search for plex.  Never heard of this before.  The only alternative media center software I know of is Media Portal and I’ve had many problems trying to install it.

Some followup questions please:
- All my computers are used computers.   They are properly licensed.  None of them came with installation media.  So, unless I can create installation media I would think it would be impossible for me to install Windows 7 as a guest on a Linux host because, as far as I know, Virtual box requires valid media to install an operating system.

Qf1.) How could I create installation media from the Windows 7 Pro software on each used  computer?  

Qf2.) McKnife suggested buying used licenses.  Where would I purchase a legal used license for Windows 10?  What vendor does this?

Qf3.) Mr. Favor:  Thank you for pointing out the problems of a Linux host / Windows guest.  I have never heard of LXD containers.  Could you send me a link so I can learn more?

Used licenses: lizengo.de (actually, they say the licenses are new and the reason why prices are low is that they are re-selling licenses they bought from MS in very large quantities)
See if you can find possible regulations that apply to your country.

Q1. For Windows 7 you need to get recovery media from the Manufacturer. Difficult if used.  Windows 10 changes this.

Q2. Likely best to look for used Windows 10 computers (that is, used computers that had Windows 10 preloaded). Windows 10 is near 5 years old so used computers should be around.

I think virtual machines as a concept to keep Windows 7 alive may be a bit complex for the average users. Better, I think, to get used computers.

Or you can convert your physical machines into virtual machines without need to reinstall Windows 7.

Hello noxcho:  How would I convert my physical machine into a virtual machine?

If using VMware, get VMware Converter (free), install it on the Windows 7 machine and run it to make a virtual machine. You need enough space (commonly about 100 GB free space)

remember that the license you have for windows 7 MUST NOT be an OEM version as OEM versions are locked to the hardware they are originally activated on. These must be retail copies of Windows 7

David is correct and my own Windows 7 machine was a retail license so I neglected to mention that.

Why all the complexity?  Windows is still dying out even if you somehow make a virtual machine.

Would used Windows 10 physical machines (OEM or Retail) not serve you better?

John, he wants the Windows Media Center.. which is a PVR and a way of sharing your media (pictures/music/video) using a full screen interface.  Microsoft dropped this and orphaned it. Like they also orphaned Windows Home Server. That is why I recommended Plex or Emby to replace the media center experience.

There are lots of Windows 10 media applications native and in the Store. So the need to keep Media Center is lessening as time goes by.

OK, thank you all for your help.  I will look at  Plex and Emby   .  I hope they are better than Media Portal.  I will not be able to convert any of my Windows 7 licenses as they are all OEM licenses.

Thank you all for giving me detailed answers!

Two points.  

1.  Shells exist for Windows 10 to make it look and feel more like Windows 7.  Not sure if thats part of your issues with Windows 10.  

2.  I want to mention Kodi (used to be xbmc) as a free alternative to Media Center.  It runs on Windows, Linux, OS X, Ios, Android and RasberryPi.   see:    https://kodi.tv/  

I have to say, I agree pretty much with David,  running Linux on the PC  would be the most  efficient use of your PC resources.  For any Windows apps you must have, you can run them in guest Windows.   I usually suggest Linux Mint to new Linux users, because it pretty much works out of the box -- little or no fiddling around with is required.  (Not that a whole lot is needed with Ubuntu, but some hardware/drivers may need some extra effort).