Alan..........
Try this.....go to this website:
http://www.codebytes.com/
Click on Sample Code and Download the Free Utility "RegFind"
Under Options, select "Search Hives" and check all six.
Next put in MicroStudio and search.....This will find all entries for MicroStudio In the Registry......Note Also Search MTU.
While keeping this program Open ......Open Regedit and find every entry that RegFind has found and Delete It.
Re-boot your computer and try the Install Again
Jim (kjzone)
P.S. Another neat Utility at the above site is the "CacheInf"