My PC friends keep sending me emails with .pps Power Point slideshow files attached. Keynote won't open them. I can click on Quick View, and Preview will open them, but not as a slideshow, and any audio is missing. In a few cases, I have been able to change the filename extension to .ppt and have Keynote open the file. But that only works sometimes.

I really don't want to install Power Point for Mac on my machine.

What are you guys doing about this problem?