I just had a new computer with Windows 8. I install AutoCAD MEP 2012 but I think I missing
design tool right at low right hand corner. Please see attachment.
What you are talking about is the Display Configuration on the Drawing Status Bar Menu. There should be a pull down to the far right of the Drawing Status Bar Menu. Once you are there, you will probably notice that the Display Configuration is unchecked. If so, select it and you should see it once again. See the attached file for the location of the pull down bar.