That may happen if that one ppt has a language setting for which the
corresponding spell check dictionaries are not installed. Can you try
creating a new shape in that ppt and typing out text with spelling errors
and see if new text gets spell checked properly?

- Chirag

PowerShow - View multiple PowerPoint slide shows simultaneously
http://officeone.mvps.org/powershow/powershow.html

"gw" wrote in message
...
Spell check in not working in one of our presentations. When we create a
new
ppt, spell check works fine. Is anyone experiencing this same issue?