You could try the following tips:
1. Click the “Settings” button to change Video settings, like higher bit rate and larger video size.
2. Close all other applications during the conversion.
Besides, PC of better configuration might produce better output quality.
This FAQ is about: Frequently Asked Questions, PowerPoint to DVD Pro, PowerPoint to DVD Standard, PowerPoint to FLV Converter, PowerPoint to iPad Converter, PowerPoint to Video Pro, PowerPoint to YouTube Converter