No need to be intimidated (at first...). Find a reliable Linux version (in Linuxese, these are named 'distros'), download and either make a bootable USB stick or burn to a bootable CD/DVD. It just works straight off the bat after you have given basic information about what language you want, what keyboard you have, and selected the drive on which to install. Do note that Linux can co-exist with Windows on the same machine but I won't recommend as the chance of Microsoft usurping the system during an upgrade cannot be disregarded. Thus, if there is any Windows remaining on the selected drive, ask the Linux installer to overwrite it.
There are literally hundreds of versions, but they group into families most of which are either 'RPM' or 'Debian'. Try Linux Mint for a very mild and trouble-free introduction to a Linux 'DEB' system, or jump straight into the later version of Ubuntu (which also is on the 'DEB' branch). Fedora (free) is one of the bigger players on the 'RPM' side, Red Hat is RPM-based but not free. However I decided to stick with Debian-variants from the onset.
If you do feel inclined to be experimental, have a look at CentOS which incidentally is a common backbone on WWW servers.