Please forgive me if there is something wrong with this post because it's my first. I also read the rules so there should be no rule breaking content. If you have any suggestions PLEASE comment because I would really appreciate that.
Now to the actual tutorial. Have you ever found yourself accidentally hitting the "update" button when starting your MineCraft client? Or maybe you want to use a 1.4 mod but your client is too new? Well here is the solution. It's called "downgrading". This is an easy fix to all your problems. This was one of my problems because I accidentally updated from version 1.4_01 to 1.5_01 and couldn't use any 1.4 mods. I didn't know this at the time but mods DO break every single update and then life is ruined (no not really, but you get the point). If you don't want to wait for an update IF the mod creator ever makes one then you can downgrade. I will also be showing you how to install the mods. Helpful tip when using MediaFire: Close the popups that come up when you download something because they are spam and will just eat up your RAM.
Tools you will need:
WinRAR or 7zip (I prefer WinRAR and that's what I use)
ModLoader (download the version for the version of MineCraft you will be downgrading to)
MineCraft Update Controller
The mod you want to install
Check your mod for additional things you may need.
Part 1: Downgrading MineCraft
1. Drag all the downloaded files to your desktop (not required but is very convenient and also recommended).
2. Open up the start menu.
3. Where it says "Search programs and files" type "Run".
4. That will open a little box that's separated into categories and under the "Programs" category there should be a little blue box with "Run" right next to it. Click on that.
5. In the dialog box enter: %appdata%
6. See the file called ".minecraft"? Click on that and don't close it until I tell you to. This is also for convenience and opening the file IS required.
7. Open the MineCraft Update Controller. Click "I Agree" when the option becomes available (usually takes a few seconds to load; I think 5).
8. When you click "I Agree" there should be a list of versions to choose from. Click the one you want and then click "Patch".
9. When it's done test it by opening your MineCraft client "MineCraft.exe" and log-in. You should see after the MOJANG logo, in the top left corner, the version of MineCraft. If it's the one you wanted then it worked. Ex. I picked "1.3_01" it should say "1.3_01" or something like that.
9a. If you're downgrade was successful and that's all you needed this tutorial for then you're free to go. If you want to learn how to install your mod then stay here.
Part 2: Installing your mod.
1. Copy your .minecraft file and paste on your desktop so you have a back up.
2. Go back to your .minecraft folder.
3. Double click bin then right-click "minecraft.jar" and click on Open with> "WinRAR or 7zip".
4. Open up the ModLoader rar file.
5. Go back to minecraft.jar and drag all the files from the ModLoader file into it. Now you are done with ModLoader! Now we can move on to the actual mod. IMPORTANT NOTE: IF YOU HAVE ANY OTHER TOOLS FOR INSTALLING YOUR MOD PUT THEM IN HERE AS WELL BEFORE MOVING ON!
6. Go to the file your actuall mod was in and open it up.
7. Drag everything except the resources folder (if there is one) into minecraft.jar.
8. Close minecraft.jar and go back to .minecraft.
9. Drag the contents of the resource folder (the one inside your mod) into the resource folder inside of .minecraft.
10. Close everything and test! If this does not work for you please post a comment telling me and I will try to help you/debug.
Thank you and I hoped this helped. If you have any questions please do comment. None of these programs belong to me (just wanted to make this clear right now). If you think I was too detailed/not detailed enough or anything else also post a comment because I would love to hear feedback so I can make this as helpful as possible.