Powerpoint File Recovery Tool
First, you should try the inbuilt functionality of MS Office program i.e. Repair and Restore and still your PPT file is not opening then go for third party tool. Remember always try the free version of every tool to analyze the software practically. here I would like to suggest Stellar Phoenix PowerPoint Recovery Tool ( http://www.softmagnat.com/powerpoint-recovery.html ) that is excellent in repairing all kind of corruption issues and extract maximum possible data from severely corrupted Powerpoint files.