Here is what I received from BlueStacks Support. Could not find all files listed, but deleted all that I could find. The utility programs listed on line 6 only listed the Registry entries needed to be deleted. I had to use regedit (just type regedit in the search window to find) to manually delete all entries. I little scary mussing with the Registry, but it worked. Could not find Notification Center or Bluestacks App Player in my Control Panel. Must have uninstalled prior. Don't worry if they are not there.
1. Quit BlueStacks.
2. Uninstall Notification Center from Control Panel > Programs
3. Uninstall Bluestacks App player from Control Panel > Programs
4. Delete the following folders if they are still present
a) C:\Program Files (x86)\BlueStacks or C:\Program Files\BlueStacks
5. Please delete all the files and folders that have “BlueStacks” in their name from the directory named temp as follows,
a) Press Windows+R
b) Type %temp%, this will bring up a Windows Explorer window
c) Type BlueStacks in the Search box of the Explorer
d) Delete all the BlueStacks files and folders.
6. [Download utility for cleaning BlueStack’s Registry keys] (http://cdn.bluestacks.com/public/tools/del-BST.reg
7. Double-click/double-tap on the downloaded file to clean the BlueStacks Registry keys.
8. [Download the latest version of BlueStacks] (http://www.bluestacks.com/
After this the installation went very smoothing and installed within 5 minutes.