If you are able to hear audio but getting a black screen, there are few possible scenarios:
1. The resolution (height and width) of the recorded video is not multiple of 4. If it’s not, it won’t play on PowerPoint.
2. AVI file is not generally recommended to insert to PowerPoint. There are number of compatibility issues reported on Microsoft Office user forum. We recommend you to convert your file into a WMV format. You can convert using Windows Movie Maker or Windows Media Encoder (free). Please note that the height and width have to be multiple of 4.
3. Please verify that you have selected PCM format for audio.
If you are not even able to hear audio, location of the video is incorrect. If you have created the PowerPoint file from a different computer, you will need to change the location.