Re: @Geoffrey W
> Now if there's something I can download onto a USB which I can then boot from and install Linux with only a few mouse clicks/keystrokes,
Years ago installing or just running a Linux distribution could be a headache, especially if you had weird hardware which many laptops had. These days you can run it on most machines without touching a Command Line Interface (CLI)
If your computer allows booting from USB (I can't remember when that became common, but some still very usable PCs don't have it, most modern ones do) then just download a 'live CD' image (.ISO) of a popular distribution (commenters above suggest Mint has nice forums, Ubuntu is common too), stick it on a stick, restart your computer, enter BIOS to adjust boot order, and restart again with the USB stick plugged in. If your computer doesn't allow booting from USB, you need to burn the ISO to a CD or DVD using an Image Writer such as imgburn.com.
Here's the thing: this won't install Linux, Linux will run from the USB stick / CD. Obviously this is slower than running from HDD/SSD, especially CD. Consider it a 'dry run' - if everything is working, you can think about installing. Even if you don't install, you now have the means to boot your computer and use some repair tools should anything ever happen to your Windows installation.
If you like it, are curious, or like the idea of an alternative desktop environment (either to use as a recovery environment or for some esoteric application) you think about installing it. This will involve partitioning your HDD. Partitioning is pretty civilised these days, but there's no excuse for not backing up beforehand. (In Windows, search for Full Disk Image Backup, and heck, create a Recovery CD whilst your at it - this way you could set fire to your HDD, swap in a new one, restore your Image and your computer is just as it was in every way. )
One little thing: should you create a Linux partition, install Linux and set up a 'GRUB'(weird names in Linux land, get used to it) boot manager (basically sets up a menu when you boot so you can choose which Operating System to use), don't delete the Linux partition or you won't be able to start Windows (fix is quite straight forward - you remember where you put that Recovery CD, right? )
A few pointers: you are a User, so the machine won't let you make important system changes unless you become a SuperUser - SUDO. Doing so involves entering your password. If you've used OSX, you'll be kinda familiar with this.
You install new software with a Package Manager - much like an App Store on Android or iOS.
Stuff has weird names.