Check out the advice in this entry from Steve Rindsberg's PPT FAQ:
Lines in PowerPoint 2000 tables have arrowheads
http://www.rdpslides.com/pptfaq/FAQ00015.htm

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Kathryn Jacobs, Microsoft MVP PowerPoint and OneNote
Author of Kathy Jacobs on PowerPoint - Available now from Holy Macro! Books
Get PowerPoint answers at http://www.powerpointanswers.com
I believe life is meant to be lived. But:
if we live without making a difference, it makes no difference that we lived
> Every time I create a table in PowerPoint and I change one of the cells
> borders - the border becomes an arrow. Is their something I can do to
> stop
> this from happening. It's really getting annoying.
>
> Thanks to anyone who helps.
Kerry K - 30 Oct 2006 16:56 GMT
Awesome advise! I was having the same problem, and this took care of it!
Thank you!
> Check out the advice in this entry from Steve Rindsberg's PPT FAQ:
> Lines in PowerPoint 2000 tables have arrowheads
[quoted text clipped - 6 lines]
> >
> > Thanks to anyone who helps.