> I have 2 EXE, AppA.exe and AppB.exe.
> I need to send cetain value to AppB from AppA in order to close the AppB
>conditionally. Any idea?

There are several ways to do it. COM would be the most likely candidate. If that's not an option, you could use memory-mapped files (http://support.microsoft.com/support/kb/articles/Q188/5/35.ASP?LN=EN-US&SD=gn&FR=0) or just use a regular table and stuff values into that.