You must install MPICH2 on all machines that you want to run MPI programs on. Run the installer on each machine individually. The installer creates the following mpich2 directory structure on your machine: mpich2\bin mpich2\include mpich2\lib The include and lib directories contain the libraries needed to compile MPI programs. The mpich2 dlls are copied to the Windows\system32 directory. The bin directory contains smpd.exe which is the MPICH2 process manager used to launch MPI programs. mpiexec.exe, also found in the bin d irectory, is used to start MPICH2 jobs.