For Office 2010:
Create a txt file. Paste the following in it
Code:
Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.pps]
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.pps\OpenWithList]
"a"="POWERPNT.EXE"
"MRUList"="a"
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.pps\OpenWithProgids]
"PowerPoint.SlideShow.8"=hex(0):
Save this file, then rename it's extension from
New file.TXT to
New file.REG
Run that file.
Or run the file from attachment.