I have used this feature a lot for text when there is just too much to fit on the screen. Go to the Developer tab and insert a text box. Open its properties and you will have a pop up window appear. Go to "ScrollBars" use the dropdown window to the right to select the appropriate scrollbar. Then insert your text and away you go. It takes a little work at first but a most usefull tool. It allows you to grab the scrollbar when the presetation is running to show the text that may be off screen. Hope this is what you were looking for.

Thanks a lot for all of you who have contributed in solving my problem ! Special Thanks to Jamtart. I hope this will make my life easier. I have spent nights to create PPT.
Now can somebody please tell how to insert Rich text box in the slide? So that I can also format my text?