This trick may save the day if you forget your fancy presentation remote control. Instead use an external mouse as a remote control.
Step 1: Connect Mouse to Laptop
This trick only works if both the mouse and the finger pad can be used simultaneously. (Older mice that use the round PS/2 connector may NOT allow both the finger pad and an external mouse to work simultaneously.)
Step 2: Remove Mouse Roller-Ball
Step 3: Cover Bottom Window on Optical Mouse
Don't put the tape directly on the LED or it may gum it up. If necessary put a small piece of paper between the tape and the mouse LED.
Step 4: Start Your Software and Position Your Mouse Pointer
Whatever your next button is, use the finger pad to move the mouse cursor over the button so a mouse click will "press" it.
Step 5: Give Your Talk
You can click the left button on the mouse to click "Next" and deliver your talk without worrying about the cursor moving off the button.
This is fast, free, simple and crude, but it usually works in a pinch!