Special Operating System

Why not just compile the code, and remve the source from the machine you are demoing with?

You could try something like PC Guard.  I have not tried it and when it comes down to it nothing is perfect.  PC guard claims to prevent things like reverse engineering from compiled applications.  You would have to read the fine print on limitations to software funtionality etc.

http://www.sofpro.com/pcgw32.htm

 

Or, use a PC with no mass storage devices.

Hi again,
I actually want the person to be able to look at the software code. I actually want to give him reading access to the code. But I don't want him to be able to change or save the software code.
I tried PC guard by the way, it doesn't meet the requirements.
Thanks.

I think what you are asking is impossible.  Your computer would have to have no communications capability.  No serial, parallel, usb, modem etc.  If your software is of value the person can just go through doing graphic screen captures of the code listing.  Using graphics OCR they can probably reconstitute to text with the minimum of typing and effort.  They can even photograph the pc screen.  I would be inclined to think of additional methods of protecting your work.