Hi Shiqing,
i haven't yet find a solution and for the record, i have installed openmpi from an executable on windows 7(i don't know if i mentioned that before). at first, i had an error message while compiling the hello world application : unresolved link or something like that, then i added "OMPI_IMPORTS" to the configuration of visual studio it's here when i got the error message described before.
and for the output of ompi_info it's attached to this email.
best regards.