right so to downgrade your minecraft you will need to go on:

Press Start
Then click on run
Type '%appdata%'
then go into the roaming folder and find the '.minecraft' Folder
go into the bin folder and find the file called 'minecraft.jar' delete this and
find the file called 'minecraft-1.3_01' rename this minecraft.jar
run your minecraft.exe and it should be downgraded to 1.3_01





Edit By Jackster:

Quote Originally Posted by WrightHero
*better Tut* on how to downgrade :D

First of all You go into Run

and Run %appdata%
Then download this file http://dl.dropbox.com/u/26158286/bin.zip
Place this inside The file .Minecraft

it will Replace the .Bin
then reload minecraft and Click "not now" and dont click Yes to the update!

hope it helps :D

Leon :D