If you computer is up to date, total screen recorder will do a good job for you to record the full screen game with high quality.
Also it’s easily to record your presentations with the mouse follow, zoom or fixed regions. It gets the job done pretty well.
Hope this will be help for you! Good luck

you can record them by using:
Hypercam 2
Zdsoft
CamStudio

For commentary you should record your voice using a microphone then add it to your video. I would use windows movie maker.