I would unload DesktopX, and then clear the DesktopX cache (delete DesktopX cache folder).
If you want to remove the Stars object altogether - delete the object from the DesktopX sub-directory after clearing the cache.
For a mini tutorial on Clearing the Cache, you can go here http://corkyo.wincustomize.com/Articles.aspx?SID=5463&AID=82461
Note - you may be able to look inside the DesktopX cache folder, and see if the "Stars" DXObject has it's own folder. If so, simply delete this folder.
Note #2 - clearing the cache will force DesktopX to start with the default settings, so you will need to rebuild your theme (if you are running one), due to the fact that saving the theme with the Stars object will create an issue for you.....