Solution:


For .PPS files (Microsoft PowerPoint Slideshow)

Start >> Run >> regedit

HKEY_CLASSES_ROOT >> PowerPointViewer.SlideShow.11 >> shell >> Show
Right-click Show and click Rename; Type the word Open so that Show is replaced by Open command [Rename "Show" to "Open"]

If you have PowerPoint Viewer 2007 installed, repeat the below mentioned steps as well.

HKEY_CLASSES_ROOT >> PowerPointViewer.SlideShow.12 >> shell >> Show
Right-click Show and click Rename; Type the word Open so that Show is replaced by Open command [Rename "Show" to "Open"]

For .PPT files (Microsoft PowerPoint Presentation)

Start >> Run >> regedit

HKEY_CLASSES_ROOT >> PowerPointViewer.SlideShow.11 >> shell >> Show
Right-click Show and click Rename; Type the word Open so that Show is replaced by Open command [Rename "Show" to "Open"]

If you have PowerPoint Viewer 2007 installed, repeat the below mentioned steps as well.

HKEY_CLASSES_ROOT >> PowerPointViewer.SlideShow.12 >> shell >> Show
Right-click Show and click Rename; Type the word Open so that Show is replaced by Open command [Rename "Show" to "Open"]