Disabling/suspending Norton

Is there any way to temporarily suspend/disable ALL of Norton AntiVirus?
 
I often have to test and/or diagnose different PCs but cannot seem to stop NAV in order to isolate functions being tested.
 
Here are some approaches that do NOT work...
- Using MSCONFIG to try to stop NAV from starting;
- Booting in Windows' Safe Mode, particularly if what needs testing is not Safe Mode friendly;
- Selecting "Disable Auto-Protect" from the tray icon context menu;
- Trying in "Settings" to turn off multiple functions that one assumes are relevant.
 
The last one above is the most tedious and involves the most guesswork. Nevertheless I have tried it multiple times and have assumed that I've temporarily stopped NAV from operating or interfering, only to then find in Windows' Task Manager that not only is NAV continuing to read and write constantly, but that its I/O is by far the highest of any process. (Before you ask, background scans were among the disabled items.)
 
Another reason for needing this ability is that in my role I've encountered a number of other software vendors that when approached about software problems have blamed co-existing Norton software. I would like to think that they are wrong, but am not prepared to have to uninstall and reinstall Norton software each time to prove it.
 
Surely there must be a straight-forward way of temporarily suspending Norton interference that doesn't involve uninstalling and reinstalling the program.
 
PS - The same issue applies to NAV's larger relatives (NIS, N360, etc.) but I'm trying to keep it simple here. Also apologies if this issue has been addressed already, but an hour was all the spare time I had to search the forum - I found similar posts but no relevant answers.