Hi
I don't know if got the idea
But in the case of Programming there are some tips:
1-VB : you can use " App.TaskVisible=False " to Hide your program
2- VC++: It's not may favorite, But I think you can make it using SystemModal
3- API : You can Hide Your own Program or other programs
Hidding Programs need different API functions in Deferent Windows
in the case of Win98/ME: You can Use "RegisterServiceProcess(ProcessID,SIMPLE_PROCESS)
and with NT series: you must use "RegisterServiceCtrlHanderA(ServiceName,IpHandler)"
To Get ProcessID you can use
a) GetCurrentProcessID

GetFirstProcess
c) GetNextProcess