To install EverQuest, click on this link to download the LaunchPad.
Either Run, or Save to your computer and then run the file (EQ_setup.exe).
You can simply follow the regular install path through the installer wich will be the most easy way to get everquest installed in your machine, don't chance any default values because you really do not need it.
After Installing the default game you only have to update it. Since everquest is a progression game, game developers constantly improve and update the content so we experience the less amount of bugs as possible.
Patches can happen once or twice in a week and normally take periods of something like 6-8 hours.
Free To Play
Some months ago, everquest was still a "only paid" game but now, you have the "Free to Play" vertent of this game where you can do almost everything gold players can do but ofcourse, you have restrictions.
All restricions about Everquest "Free to Play" can be found here: