Sirs, I am trying to run some sample parallel problems using openmp, hybrid openmp and MPI using Gfortran in my laptop which has an Intel i7 core processor and uses Windows 8.1. The openmp examples run fine. But, the hybrid ones using openmp and MPI fail with the message : "cannot read "mpif.h". I tried replacing mpif.h by " use mpi", per suggestions found on line and this also does not work. I downloaded the mpif.h from a website. I will be grateful for your help in resolving the problem. If there is a special version of mpif.h for windows 8.1, do let me know how I can download it. I have a 64 bit machine and I downloaded the 64 bit Gfortran from the Gnu site. Thanks for your help Yours sincerely, V. Thiagarajan