Linux users don't need to learn or tinker with the CLI (dos-like 'terminal) if they're happy with a totally Windows-like user experience. (Native Win apps run in 'Wine' therein if you like EXCEL). I suggest anyone Linux-curious dig out an obsolete (or unused) Win machine and run a 'live CD' session. (Download .ISO and 'burn' (not copy) to DVD, boot from it). I like LXLE for laptops, and use Linux Mint 17 on my power desktop more often than I boot it to XP.
Your old OS won't know it's running on another, borrowing RAM and some HD space for temp cache. (It will run more slowly than a full install, working from the DVD vs the HD.) Many versions have the option to install Linux in a dual-boot configuration from the live session. You'd want to read up on setting up a boot-loader if so, and may want to use a disk partitioning utility prior to installing. Instructions for these are easy to follow and come with the "are you sures" for the tricky bits.
When turning on the computer you would select Win or LINUX from a menu and go from there. I typed a post or two yesterday on another box running an OS that can be run entirely in ram and booted/backed-up to a pen drive ... on a computer with 500MB of RAM & no hard drive. (Firefox is Firefox & works the same on my XP, Vista, Win 2k, and Linux machines.)
What /pine says about 'any old' computer is because open source software has such humble hardware requirements. (Choose a 'non PAE' distro for those 486s, ok? ...

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