Free Software Downloads That May Help:

PowerPoint Viewer 

          http://www.microsoft.com/downloads/en/details.aspx?FamilyID=cb9bf144-1076-4615-9951-294eeb832823

     OpenOffice.org 

         http://www.openoffice.org/

Check your default file settings

    Windows XP - Start; My Computer; Tools; Folder Options; File Types 

    Windows Vista & Windows 7 - Start; Default Programs; Associate a file type or protocol with a program

Check file extensions for Proper Program to Use

     http://filext.com/