Hi
I don't really understand what you are trying to do here
If the installation writes a registry key, then the program needs that key to run. On the other hand if you are trying to say you have uninstalled the program and the key is still there, well you should be able to delete it. If you can't then there is something in the startup that is writing it. So check what's in the startup group and if there is nothing there to do with the program and you still can't delete it run in safe mode then delete the God darn thing
/hobferret