ModLoader is one of the most popular Mod for Minecraft that doesn’t actually do anything in game. ModLoader as it says in its name, loads Mods. ModLoader makes it easier for you to install and run any Mod, and it has been the platform that most Minecrafters have to use to be able to make there Mods run in the game.
You will only need to use ModLoader to install Mods when the Mod you are downloading tells you to get ModLoader. Also please note when installing Mods make sure you have the correct version of ModLoader to go with your version of Minecraft, and if you are using the most up to date version of Minecraft make sure you use the most up to date version of the Mod and of ModLoader.
How to install is easy but I will show you how to do it with Mod X
How to Install ModLoader for Minecraft 1.7.4 and 1.6.4
- Download and Install Minecraft Forge
- Run Minecraft Launcher and select Forge Profile
- Go to Start Menu and Run %appdata%/.minecraft
- Put the Modloader file without extracting it into the mods folder
- Launch Minecraft with the Forge Profile