Before reinstalling you need to delete the feeds entry in:
C:\Users\<user name>\AppData\Local\Microsoft\Feeds\http~c~f~fthemeserver~dmicrosoft~dcom~fdefault~daspx~mp=Bing&c=Desktop&m=en-US~.feed-ms
Once this file is deleted you will have no more problems reinstalling bing dynamic. The reinstall will work correctly.