"Just go to Control Panel\System and Security\System.
Click the "Advanced System settings" link on the left and it will popup with a system properties box.
Click the environment variables box at the bottom of the "Advanced" tab.
ANOTHER box will pop up with user variables for your system. If there is a variable "_Java_Options" with the value "-xm -1 -xm -1".......DELETE IT. Confirm deletion. Click "OK" at the bottom of the Environment Variables box.
I have made this final video to all of you who couldn't understand the instructions.
Download minecraft.jar. The jar is executable and might work as-is. If you run into memory issues, try launching it with java -Xmx1024M -Xms512M -cp Minecraft.jar net.minecraft.LauncherFrame, also please use Sun's JVM."