Thank you for your suggestion.

In fact, what I do is Program A will update Program B, if there is..., then if Program A find there is a update for program A, program A launch Program B for update & quit itself... That's working fine now... by just including in main.prg of Program A

IF file("filelist") && A list of files for updating, programmatic formed by Program A while logging in
  RUN/B programB.exe
ENDIF