If you want to embed PowerPoint presentations in your posts you have to go to www.slideshare.net and create an account.
Once you create an account you can upload your presentations onto the website. The website will give you two options “Upload publicly” or “Upload privately”.
If you want to upload something which is private and you do not want to share it with others you will have to go for “Upload privately” which unfortunately is paid. And you have to become a Pro.
But if you don’t mind making your presentation Public go for “Upload Publicly” which is free. Once you upload your presentation, the website will give you an HTML code for your presentation. Once you get the Html code you can embed it in your post as any normal embedding of YouTube videos is done.
Try it and if you have any issues feel free to get back to me.