How does this sound to both you and @Dov? I have a ~10-12yr old Dell Optiplex sitting around collecting dust. I could do a step by step, in simple terms, walking through the process of installing Linux Mint, issues to look out for, etc. Then we can go from there, and I'm sure some others will chime in with other advice to that end. If so desired, we can also expand on that and I could walk through how I would go about upgrading components in an old machine to keep performance at a respectable level. I need about 1 week before I can start in on that, as I have some things to take care of.
I'm currently posting this from a 14y/o Dell XPS desktop that runs perfectly fine and is plenty fast for everyday internet, spreadsheet, word doc, etc type stuff most of us do. I have newer, faster, machines but, this is the daily beater because it just keeps working so why replace it. For regular everyday usage like this, the performance issues people often run into are usually found in at least one of two areas:
- OS / software bloat
- Dying hardware: hard drive, ram, video card
On the software front, with each passing year, most software companies add more and more "telemetry" and privacy-invasive features. Often marketed as convenience features. The end result is, as you install more programs, if you're not staying on top of controlling what runs on startup, what runs in the background, etc. you might have tons of stuff running even though you might rarely use most of it.
On the hardware front, while it can sometimes be difficult to diagnose issues, physically replacing a hard drive, ram, or video card isn't that hard and anyone can learn. Usually a few screws, cables, and you're done. The difficulty is in ensuring you install the right drivers, or getting a new hard drive formatted and ready to use. If replacing a boot drive that has your operating system, that can get a little more tricky, however there are options. For example, there are some programs you can use to easily clone your boot drive. They don't always work perfect but, there are options and some of them have a fairly low barrier to entry in terms of tech skills.
In terms of hardware, I still tell people that ~5-10y/o Dell XPS, Optiplex, or Precision series desktops are some of the best bargains. You can usually find many of those anywhere from ~$80-500+. They're plentiful on eBay, and used or refurbished from some respectable retailers (Newegg, Discount Electronics). Everyone thinks they need a new PC every other year, so those that are even a few years old end up being pennies on the dollar from their original prices. Dell also does a pretty solid job with a lot of their hardware, cases, spare parts availability, etc. Combine a good buy of an older machine plus a bit of hardware (max out ram, fast SSD hard drive, better video card, etc) from Newegg or careful eBay purchases from tech salvage companies, and you can end up with a decent "daily driver" for a few hundred bucks that'll last you another decade, or at least until SkyNET takes over.