For computer playback, it is adviseable (when ever possible) to start off your animation with about 2 seconds of black. If you do that, then that should take care of your missing frames at the front.
If you’re going fullscreen then set your bitrate to about 3-6Mbits. Set audio to mono if you don’t require stereo. use constant bitrate cos’ if you’re not using a dedicated compression programme, chances are that the application you’re using for the compression may not implement VBR very well and that plus a low datarate may explain the pixelated text. What datarate you should set depends largely on the type of material you have.
Your other option is to use MPEG-2 with a datarate of about 8Mbits, which is essentially up to DVD specs. Actually you may want to lower that to about 5-6mbits to cater for the extra overhead on your system due to PowerPoint’s hit on system resources.
Cheers
Roland Kahlenberg
https://www.broadcastGEMs.com – Adobe After Effects project files
https://www.myspace.com/rorkrgbspace