If you are using an older computer and it is tortuously slow and you can't upgrade the RAM or swap in an SSD but you *can* install software, I would strongly recommend installing Linux.
The vast majority of people these days use computers primarily for web browsing and occasionally use an office suite. Most people don't even store their music or photos on their computers these days. If your computer is basically an internet machine that you don't use for anything other than browsing and basic word processing/spreadsheets, then there is no reason not to switch to Linux.
I would recommend installing Linux Lite, which is a well-supported, widely-used distro that most computers built within the last twenty years should be able to run. It's called "Lite" because it is an operating system that requires minimal processing, storage, and memory to run.
To do this you will need:
- A 4GB USB stick or a blank DVD to create installation media
- An internet connection to download the software
- Another computer or phone that you can use to follow the instructions, or a printed/written copy of the installation guide
- A computer on which to install Linux. Installing Linux as the sole operating system on this computer (which is my recommendation here) will mean that everything else on the computer is deleted. Save all of your files/movies/music/etc. to a backup drive or another computer before you install Linux, because installing a new OS will delete literally everything on the computer and make it impossible to get back.
Follow the instructions for installing Linux Lite, and then you can install software on your new OS. Linux Lite comes bundled with Libre Office, which is a free office suite like Microsoft Office that has programs similar to Word, Excel, and Powerpoint. It installs with Chrome, so I would recommend installing Firefox and uninstalling Chrome as soon as you're able to get on the internet.
After that you can pick and choose from a wide variety of linux-compatible software and you can use your computer as a regular computer. I'd say that it's probably a good idea to be picky about what software you install, and to try to keep your computer as lean as possible if you're trying to get a longer life out of an old device.
There are a lot of people in the notes who are saying "my computer can't even load four tabs" or "my computer can't even open the software I need to do this" and if that is your computer I think you've pretty much got nothing to lose from installing Linux. If your computer is essentially unusable in Windows then it's probably not going to be *less* functional in Linux, unless you're keeping the computer the way that it is for some very specific software you're using.
A lot of people think that they can't uses Linux because it's entirely in the command line or doesn't have a graphic interface or something, but most linux distros only look about as different to users as windows does to mac or vice versa.
This is what the Linux Lite default desktop looks like:
It's got a start menu and a task bar and folders on the desktop, same as any other computer. It's very easy to use and has the help manual installed right there as soon as you're up and running so that you can troubleshoot your way through any issues.
Really, seriously: if your computer is slow as fuck and all you use it for is web browsing, this will make your computing experience significantly better without having to buy anything but a thumb drive.