I had this exact same problem, but with Pictures. The presentation was 100
slides long, with many pics on each slide.

The file was working fine, came back the next day, and WHAM! get a redraw
of the first slide 100 times (and slow at that).

Even after deleting all slides but the first, it still redrew forever.

After many hours, figured out that the master side had a background color
set to gray. I deleted the back ground color from the master, and PRESTO!
no more problem.

I rechanged the color to gray, and it's working great.

Interesting note: The issue occured on several computers with the same
file, but not others... bizzare.

In the past, this has had more to do with the graphics acceleration used by
the computer than the background color.

You might want to try setting your hardware acceleration back a notch or two
and see if the problem goes away.
***How to set graphics hardware acceleration back
http://www.pptfaq.com/FAQ00129.htm

--
Bill Dilworth
A proud member of the Microsoft PPT MVP Team
Users helping fellow users.
http://billdilworth.mvps.org
-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_-_
vestprog2@ Please read the PowerPoint FAQ pages.
yahoo. They answer most of our questions.
com www.pptfaq.com
..

"ProsperousOne" <ProsperousOne@discussions.microsoft.com> wrote in message
news:C4A8DE82-3078-42C9-8115-4BA0ADC34000@microsoft.com...
>I had this exact same problem, but with Pictures. The presentation was 100
> slides long, with many pics on each slide.
>
> The file was working fine, came back the next day, and WHAM! get a redraw
> of the first slide 100 times (and slow at that).
>
> Even after deleting all slides but the first, it still redrew forever.
>
> After many hours, figured out that the master side had a background color
> set to gray. I deleted the back ground color from the master, and PRESTO!
> no more problem.
>
> I rechanged the color to gray, and it's working great.
>
> Interesting note: The issue occured on several computers with the same
> file, but not others... bizzare.