I was making a presentation

[NaifHamidou]

It was couple of days ago, I almost done, but the light was unexpectedly off. I rerun computer, opened .pptx file via PowerPoint 2007 and didn't see many latest changes.

 

[AlienMenace]

Silly question from me, while you were making these changes. You were hitting the save tab from time to time weren't you.

 

[AuroreAsselin]

It was couple of days ago, I almost done, but the light was unexpectedly off. I rerun computer, opened .pptx file via PowerPoint 2007 and didn't see many latest changes.

Only in case nothing helps, then there is more powerful thing as powerpoint restore

This blog might be too effective - http://www.presentermedia.com/blog/2012/08/i-cant-open-a-powerpoint-presentation-in-2010/

You may read useful article: http://www.pptfaq.com/FAQ00108_Recovering_a_corrupt_presentation.htm