Revising xml slideshow

I have used your code to make a revised version which needs to peridocally update the .xml file. Getting a new file loaded is not my problem, the problem lies in the fact that loading a new file does not kill the old one. After a while I have many files running simmultaneously fighting each other throwing everything off. Is there any way to kill the old file and only run the new??

Thanks,
-Luke N.