Finding the program turned out to be no problem. Be sure to download the latest version, 7.39, as of this writing, August 2011. I used this link ( http://www.geocities.jp/higuchuu4/pict/MikuMikuDanceE_v739.zip ) to download my copy, but as of 9/28/11 it does not seem to work. So I have added my own downloaded Zip file to my site for you to download:
It is a 5mb download ZIP file. I SAVEd it to my Desktop. When you have it, open that zip folder and click the command “Extract All”. I just agreed to the defaults and found a new folder on my desktop containing MikuMikuDance … ready to run. I dropped the ZIP folder into the MMD folder just to keep it. There is no “installing” MMD. It sits in its folder on your desktop, ready to use. If you decide you don’t want to keep it, just drag the folder into the Recycle Bin … there is no “uninstall”.