Just follow these steps, and you'll be able to show all your good videos on powerpoint presentation. Just 3 simple steps, and you can present your powerpoint with videos without online at all:
1- download the youtube video with "zillatube". Get the program from http://www.zillatube.com. This program helps to download and convert those videos the fastest way possible for your powerpoint. It also has the powerpoint conversion option for you select.
2- using zillatube, convert it into powerpoint or wmv video format.
3- final step, a simple step, just insert movie file(using the file menu above the powerpoint program) the powerpoint or wmv video into power point.
(Note: make sure the powerpoint video is placed in the same folder with your powerpoint file, then you can bring the folder to any computer and view it)
all the best to your presentation.
Get the program from http://www.zillatube.com