Mouse Emulator is a freeware program that allows you to run Windows without a
mouse. If your mouse becomes ill, or if you just want to see how a keyboard
mouse might work out for you, try Mouse Emulator. 

Mouse Emulator can also toggle mouse buttons with a simple key press. This is
very useful for RSI users that have problems with drag operations with the
mouse. 

http://www.geocities.com/pronto4u/mouseemulator.html