>>Hello, i need to give the demo of a program i made but i want that after 2 months doesn't work or allow to work, how can i do this?>>

Include in you setup file a dll to be copied to the destination PC.
then everytime your main prg runs, it checks the date if certain condition meet then delete the file..

It seem like this,,

Get first intall windows and system dir..store to a variable the path plus your dll file or other file that you Demo system needs to check before it proceed to execute your next code blocks.

SET DATE TO BRITISH
SET TALK OFF
ddatelimit = CTOD("10/10/2004")
If !File('yourfile.dll')
    QUIT
ENDIF

If date() >= ddatelimit
   If file('yourfile.dll')
      dele file yourfile.dll
   Endif
Endif
*// Code blocks..