how to create a clickable button in powerpoint

you can insert HTML code to gmail.here it is.
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All you have to do is click on the "Compose Mail" button, just like you normally would to open a new message you want to send. When the page opens click on where it says "Rich formatting". A whole new list of buttons will show up that you can use to create your HTML formatted email without ever having to actually use HTML.

Change backgroung colors and text colors. Make things bold, italic or underlined. Add hyperlinks or bulleted and numbered lists. Change your font styles and font sizes. Indent and align your paragraphs. Answered May, 07 2011

Well, you can refer to this way:
1 Open Flash CS4

2 Click Flash File (Actionscript 3.0)

3 Create a symbol with Insert>New Symbol

4 Draw a light green rectangle

5 Make a text box and type anything you want

6 Center the text in the middle of the rectangle

7 Select everything

8 Name the file "button" and choose button from the drop-down box

9 Create a keyframe underneath where it says "Over" on the timeline

10 Fill in the rectangle with dark green, making sure the text isn't selected

11 Choose Edit>Edit Document to return to the document

12 Open the Library and drag the image of the button to the work area

13 Test the button by choosing Control>Test Movie

The source:http://www.wikihow.com/Make-a-Clickable-Button-in-Flash-CS4 Answered May, 16 2011

here is the answer:
How do i make a link "clickable" on a powerpoint Answered Nov, 25 2010