If you are unable to open PPS attachments in windos mail this tool help to fix it. Shyam Pillai has developed a small (128 KB) program that will correct the problem and allow you to open presentation file attachments directly from your email. With slight modification your can fix it for Windows mail as well.
1: Extract the file
2: Right click and run as administrator And Allow to RUN
3: Once done, You will get a prompt " the program is not installed properly.
4: select the option " the program is installed correctly'
Open the PPS attachment from windows mail: It works