Bullets in PowerPoint also seem to bother me. They never seem to start or end when I want. I also noticed today if you use a hyphen it will "auto correct" these into long dashes when trying to use them as a bullet.
The away around this in PowerPoint (and Word) is to use a hard return (Enter) and then hold down ALT, then type 0149, and then let go of the ALT key. This should give you a nice solid bullet. Repeat as needed.
I do not recommend this technique in web pages (HTML) where you may want to convey semantic meaning with an Ordered or Unordered List.