Hi Bonnie: I dug through some old notes I've got. I'm no expert, but here
is a bit of material that might help you. I've cut and paste them into one
message here.

If you are using Jaws, you can read the powerpoint file without the need to
convert it to any other format.
When you open the document in powerpoint, press f5 to get the slide show,
then you use your normal arrow keys to read.
Jaws also provides some shortcut keys that you can use to navigate around
the file, you can press insert+h to get to them.
You can also press (application key) then choose go to slide sub menue, this
will enable you to explore the titles of all slides in case you like to go
to one of them in particular.
If you like to move to the next slide, just press space bar.

when you open your presentation in PowerPoint, press F6 to cycle through
the status bar, ribbon, and various panes. In Jaws, you move through panes
for notes, slide thumbnails, and slides. In NVDA, you only move to the slide
pane/area.

When you're in the slide area, the screen reader announces the title of the
current slide. Press the down/up-arrow to move to the next/previous slide.
Again, the screen reader announces the title of the next/previous slide. If
you're in the slide Thumbnails (with Jaws), you can alternatively press
space and backspace to move through the presentation.

Once you're on a slide you want to edit, press tab. The first thing you come
to is the title of the slide; arrow or start typing to edit/translate. When
you finish working with the title, press escape to exit editing mode, and
press tab again. the next thing you come to is the content area, which
normally contains a bulleted list. Again, press an arrow key or just start
typing to edit/translate. Again, when you finish, press escape to exit
editing mode, and tab to find out if there are other edit fields on the
screen.

My own experience is that, tables, charts, and so on are often inserted as
objects, so they're not always accessible. Occasionally, even the bulleted
lists are inserted this way, so you can't really edit. You have to print the
presentation out, scan it, and retype everything manually.
also, these objects aren't always included if you convert the file to rtf.

When you finish editing/translating your slide, press F6 several times to
get back to the slide area. That seems to be the only way to move out of the
individual slide with both screen readers. With NVDA, you sometimes have to
press F6 to cycle through the status bar, etc., a couple of times. when you
are back in the slide list, down-arrow to the next slide. then press tab as
before and start editing.

That's all there is to it.

If you're creating slides, go into the insert menu and select New Slide.
Tab to the first edit field, enter text, hit escape, tab to the next edit
field, enter more text, hit escape, etc. When you're done with the first
slide, go back into the Insert menu, select New Slide, and so on.
To return to a previous slide, press F6 repeatedly to move to the Slides
list, arrow to the slide you want, press tab, and start editing.

Gudrun