To disable the vertical ruler in Microsoft PowerPoint, follow these steps:

1. Open PowerPoint and navigate to the slide where you want to disable the vertical ruler.
2. Click on the “View” tab located in the ribbon at the top of the PowerPoint window.
3. In the “Show” group, you will find the “Ruler” checkbox. Uncheck the box next to “Ruler.”
4. The vertical ruler will now be hidden from the PowerPoint window.

Note that disabling the ruler will affect all slides in the presentation, not just the current slide. If you want to disable the ruler for a specific slide only, you can do so by adjusting the slide layout.

1. Switch to the slide where you want to disable the vertical ruler.
2. Click on the “View” tab in the ribbon.
3. In the “Presentation Views” group, click on the “Slide Master” button.
4. The Slide Master view will open, displaying the master layout for your slides.
5. Locate the slide layout that you are currently using for the slide where you want to disable the ruler. It will typically be the first thumbnail at the top.
6. Right-click on the slide layout thumbnail and select “Format Background” from the context menu.
7. In the “Format Background” pane that appears on the right side of the screen, go to the “Slide Background” section.
8. Check the box next to “Hide Background Graphics.”
9. The vertical ruler will now be disabled for that specific slide.
10. Close the Slide Master view and return to the normal PowerPoint view by clicking on the “Close Master View” button in the ribbon.

Now, the vertical ruler will be hidden for the selected slide or for the entire presentation, depending on which method you used.