Macro security warning when no macros are present
Macros and Active X controls can be persistent little critters. You may get security warnings even after you think you've deleted them. If so, here are some things to try:
Press Alt+F11 to start the VBA editor.
Choose View, Project Explorer (or press Ctrl + R) to open the Project Explorer pane. In it, you'll see a list of all open presentations.
Locate your presentation and doubleclick it to view its contents. If there's anything shown (Modules, Classes, Forms), rightclick each in turn, then choose Remove from the pop-up menu. Export them before removing them if you want to preserve the contents.
If you see any Slides among the other modules, etc. it usually means that there is or was an Active-X control on that particular slide in your presentation.
Remove then re-create any slides that have or once had Active-X controls