Problem With Modloader

I have finally figured out what is going wrong with modloader and Minecraft crashing. If you have previously installed mods on Minecraft sometimes files get put into the .minecraft folder in general. To fix the problem with modloader you must delete all previous 1.8.1 or earlier content in you .minecraft folder. After this, modloader should run perfectly. Please don't post any comments saying I'm so dumb that I didn't figure out or something like that because a lot of people are having trouble figuring out what's wrong. Please give diamonds so people can see this blog and fix their Minecraft.