I started on a Timex Sinclair 1000 PC.  If you don't know what that is, Timex made watches and they decided in the early 80's to have a go at making a home computer.  The thing was about half the size of my current keyboard, ran black on white graphics, 2K RAM but I had the 16K memory expansion!  The CPU was the Z80 microprocessor with built in BASIC. The only form of long-term storage was cassette tapes. I got this for $69 back then and that was a week's pay for me.

We cannot hold on to everything forever.  I am all for recycling the broken and refurbishing the old to make new again.  However some stuff belongs in a museum. My prior posting (only minutes ago) explains that my nephew and I refurbish PCs give them new life and many get sold, or given to elderly or families with low incomes.

Back in 1996, I worked for a national electronics sales retailer, that year PCs outsold Televisions.  Customers were buying 486 PCs for $900 and the cheaper 286 PCs were running about $350. This was a major investment and they wanted to know, "How long will this model last? Am I going to be told this will be obsolete next month?".  I answered them, "There is always some nerd adding something on or improving something.  Next month they might come out with cup holders and ash trays, but that is the nature of the beast.".  I explained in the most simple terms that current production was underway on 586 processors (Pentiums) that once those were available, the geeks and neckbeards would be hard at work on 686 processors.

I play some games on my PC, I am not all work and no play.  If you are playing the latest and greatest Call of Duty online, you will need that high end gaming PC that runs the Windows 10.  But I don't play the best of best of best... I play some very mild stuff and I also play some old Windows games using WINE or DOS Box.  By old, I am talking 2000 to 2010 and not 1980's Pac Man.  All the RAM and CPU speed is driven by the needs of the gaming industry.

Speaking as a nerd and a geek, from a programming point of view, I can see many areas where the games could be reduced in bloat.  Back from 1985 to 1995, I wrote all my programs from scratch.  There was no "add ons" or external programming required. Today programmers take short cuts by using Nvidia graphics API, PhysX, DirectX, and Steam API. Back in my days of C and Pascal, we had OOP (Object-oriented programming) a programming practice of "objects", which can contain data and code from other programs.  But most of the time, we wrote those external programs.  Today's program designer no longer needs to know the details as long as they can call out to other programs for their needs.  The whole system has become less about coding and more about linking nodes and modules to each other.

I recommend anyone comfortable with their PC, just remain in place, until you are no longer comfortable.  When that occurs;

• Upgrade your software first
• Upgrade components second
• Upgrade hardware third

Your final option should be to replace the computer, but please find your old one a home, and don't give it to the dolphins, as they cannot use them without fingers! 

If you feel security is an issue here are a few suggestions;

Raspberry Pi https://www.raspberrypi.org/  makes tiny affordable PCs about the size of a pack of cigarettes. They are very cheap ($55 to $150) but what is more important, one can use it to secure a network. Here is a video tutorial about setting one up.  https://youtu.be/IV1K6N_2JeM 

The idea is you can use the micro to filter DNS and set up a system where any tracking apps and adverts good enough to get through the router ends up blocked by a tiny micro.  These are pretty good for work areas too, my Optometrist set all his office equipment up with these micros.  The HDD is a micro SD card the only moving part is the optional fan. 

Now if you are just running one machine 24/7, and not a bunch of other devices on a large network, you can install pi hole on any Linux software from https://pi-hole.net  be sure you do take time to absorb some video tutorials prior to installing or you could end up shutting your network down.  Please be careful with anything you choose to do with your system.

Networking security is a multilayered system.  You can't just lock down one thing and expect it to keep out all intruders.  The NSA stated Linux is the most secure OS available to the public and they proceeded to make their own distribution.  Here is the link to their SELinux page.
 https://www.nsa.gov/What-We-Do/Research/SELinux 

But my primary concern isn't DNS, Linux distributions, or hackers "out there" trying to get in my PC.  The apps and advertisement block were addressed by using Pi-Hole to block them, but what about the browser and online games.  Anything allowed to access the internet is a potential virtual spy inside your system.  How much can we trust Google Chrome?  It is an open source project and Chromium is available. 

SRWare Iron is a Chrome alternative. The browser is based on the Chromium-source and offers the same features as Chrome - but without the critical points that concern the privacy of its users. 
https://www.srware.net/iron

In the 1990s, the lack of security on the internet and its ability to be used for tracking and surveillance was becoming clear, and in 1995, David Goldschlag, Mike Reed, and Paul Syverson at the U.S. Naval Research Lab (NRL) asked themselves if there was a way to create internet connections that doesn't reveal who is talking to whom, even to someone monitoring the network. Their answer was to create and deploy the first research designs and prototypes of onion routing.

Tor Browser 
https://www.torproject.org

Using the SeaMonkey default browser on LXLE is just fine, but either of these two browsers will give you peace of mind.  That should give you some things to consider as you set up your secure system.

True to this point, that software controls the hardware, but there has been concern that hardware companies will slip in a CPU identity reader.  When the CPUID was introduced in 1993, I recall reading a lot of conspiracy pages about the new chips with the serial numbers on the "inside".  Today, in any OS, you can see the CPU UUID with your OS;
sudo dmidecode | grep -w ID

Returns my CPU serial number;
ID: A7 06 02 00 FF FB EB BF
ID: 255
ID: 255
ID: 255
ID: 255

sudo dmidecode | grep -w UUID

Returns my serial number unique identification code, only my PC has this unique code;

UUID: 02CC4000-7D63-11E1-0000-E8393558991E

That comes from the hardware and is only read by the software, or apps that could request it.  I am not that "paranoid" to believe the world is out to spy on me.  But the point is, there is plenty of hardware and software to block it these days. 

History of the Gulf War in 1991, tells the NSA planted chips within a French printer that contained viral code and then sold or smuggled to Iraq military.  Hardware can be your bane, if someone wanted it bad enough.

How could this feature be abused? You download an app and it reads your CPU ID then broadcasts it back to base (whoever is logging them) and you jump on Facebook  the app on there now links that CPU ID owns access to that Facebook. Now let's assume the worse, the app isn't downloaded but is on the chip itself.  The chip is broadcasting the information each and every time you go online.

There is no question about it, hardware can be used to identify you online. But I seem to lack the ego needed to be worried that I am important enough to be spied upon.

Pi 400 is the way to go. My nephew gifted me his Pi Zero, it is very slow to boot up. He has them all, from Pi 400 (white and red keyboard) to the PiBoy DMG (hand held) retro gaming.  I find the PiBoy amusing - but also it is shade of gray - when it comes to your ethical values of downloading ROMs.  The pi-hole software can be downloaded free to run on any Linux distro, the tiny machine can act as a DNS filter keeping out advertisements.  I find them fun to experiment with, my first home PC was a Timex back in the early 80's.  It was small but only held 2K or 16K with the RAM expansion.  You can see an old Timex in the interactive movie "Black Mirror: Bandersnatch" (2018) on NetFlix.  Have fun!