See Open a document after a file corruption for the repair steps. If you get a message that says, 'PowerPoint could not open the file' or 'No text converter', you probably have a file-corruption problem.

'PowerPoint could not open the file', or 'No text converter' ppt format, you can open it in PowerPoint 2007 or a newer version. In the Save as type box, choose Presentation (*.ppt). Use Save As, because the file must be saved in a different format.) To fix this problem, you need to change the underlying format of the PowerPoint 95 file: PowerPoint 2007 and later versions are unable to open a presentation that has been saved as a PowerPoint 95 file. PowerPoint can't open the type of file represented by. The problem may be a file-format issue, or it may be a file-corruption issue that requires repair. If you opened the file from a disk, try to open another copy of the file on a new disk. For example, if the file was sent to you in an e-mail message, have the person who sent the message send it again, and then try to open the file again. PowerPoint has encountered errors and can't open this file.

Open office presentation