access mpirun instead mpiexec

[mehdikia2519]

hello everybody
According to the documentation on the web for using Opensees parallel executable (i.e. OpenSeesSP) it is necessary to install MPICH2 to have mpirun .it is done but i have mpiexec on my computer instead of mpirun so it is not possible for me to run openseessp . is there somebody to tell me how can i have mpirun instead of mpiexec?
it is worthy noted i use windows 7 -64 bit operating system
thanks

[fmk]

mpirun and mpiexec are the same. some systems call the exe mpirun, others mpiexec.