stopping nsi.exe

I am trying to setup an SLI bridge between my Nvidia video cards. Every time I click on apply - it tells me that "nis.exe" is a "blocking program" and I have to close it.

I go into task manager and try to close it and it gives me a "Task cannot be completed" error message.

How can I close "nis.exe" (temporarily) to apply changes for the SLI install?

Thanks in advance.