There are a few:
.pot--PowerPoint 97 to 2003 template file
.potx--PowerPoint 2007/2010 Open XML presentation template file
.pps--PowerPoint 97 to 2003 complete slide show file
.ppsx--PowerPoint 2007/2010 Open XML complete slide show file
.ppt--PowerPoint 97 to 2003 Presentation file
.pptm--PowerPoint 2007/2010 macro-enabled Open XML presentation file
.pptx--Microsoft PowerPoint 2007/2010 Open XML presentation file
PPS files or Powerpoint show files are from the program Powerpoint. Powerpoint is made by Microsoft. Therefore, you can find information on these kinds of files on the Microsoft website.
Powerpoint files can be opened in the Open Office Presentation section. Select a New Presentation from the File menu. Select the Open Existing Presentation option. Click the Open... button and select your Powerpoint file. Powerpoint files with the extensions .ppt .pps .pot .pptm .pptx .potm or .potx are recognised.
Yes, you can use files saved on Microsoft PowerPoint 2003 in Microsoft PowerPoint 2007 (but not the other way around).
They're used as extensions to identify picture files.
OpenOffice or LibreOffice can open PowerPoint presentations.
PowerPoint files can be viewed on a Mac with Microsoft's PowerPoint, Apple's Keynote, Open Office and several PowerPoint viewers.
not as of now
Yes you can.
Probably antivirus script built in PowerPoint to prevent you from viruses coming from PowerPoint files.
You Can Use openOffice or libreoffice open or edit powerpoint files on Mac
In this case you can try software-based instrument restoring powerpoint files of any version MS PowerPoint. You may look at tool below.
PowerPoint only accepts .avi,.asf and .mpeg video formats.