Everybody has their own opinions when it comes to operating systems Triboy, so you'll probably get a confusingly large number of suggestions.
In terms of Windows 10 I have done an upgrage from Win8 to 10 and set up a brand new Win10 machine. I would say (my personal opinion and one I'm not going to argue with anybody about
) that even on the brand new machine Win10 was frustratingly slow. My assumption would be that hardware that came with XP or Vista installed will be more or less unusable with the demands of Win10.
Therefore if you wish to stick with Windows then buying new hardware with Win10 already installed is probably going to be the best bet - the money spent buying an upgrade to Win10 is almost certainly better used on new hardware.
Whilst I'm mainly a Windows user, I have regularly used Linux on older hardware - mainly for internet browsing, occasionally for tasks like hard disk recovery that Windows doesn't do as well.
The main thing with Linux is not to be put off by all the different names and versions. You can safely ignore 99.9% of them if you want. However, because most versions are available without any cost it is certainly worth trying a few different ones to see which you are most comfortable using.
Most of my early experience was with Puppy Linux - it is great for beginners, friendly and is available in versions which are tiny in terms of disk space and memory requirements.
More recently I've started using Lubuntu, which is a version based on Ubuntu. Ubuntu appears to me to be emerging as the most popular version of Linux - though again that is my personal opinion
Lubuntu is a 'lightweight' version of Ubuntu which has been optimised to work on older or lower spec equipment. I'm quite happy with it so far. It is running on an old laptop which came with Vista but became unusable due to overheating. Vista was making the processor work so hard the cooling system couldn't cope and the laptop powered down as a protection. No such problems with Lubuntu.
Some versions of Linux (including Puppy and Lubuntu) can be set up to boot from a CD or USB stick. If you want to try Linux before you decide what to do then just download whichever version you like the sound of, create a CD/USB and boot your machine from that. There is no need to do anything which will harm or remove your existing Windows installation if you just want to trial Linux (but might be an idea to do a backup just in case!).
It is also possible to install Linux on the same hard disk as many (all?) Windows versions with built in software that allows you to choose whether to run Linux or Windows when you boot. that way you can keep your existing version of Windows as a 'just in case I need it' whilst you use Linux for your day-to-day activities.
The only negative side of Linux for me is that you cannot simply install and run windows programmes on it. There are methods that allow you to run many windows programmes, and there are many very good alternatives (e.g. LibreOffice). But you need to find out if you are prepared to go without a favourite windows programme if it cannot be made to work under Linux.
In terms of ease of use and user experience, many Linux versions are very similar to Windows. If you are currently using XP or Vista then the learning needed to use something like Lubuntu is roughly the same as that required to start using Windows 10.
Hope that helps.
