I have a code originally written for high performance computers (UNIX). Is there any way I can compile and run the program on a multi-processor windows workstation?
I have ran Fortran applications on both Windows and Linux based clusters without ever having changed any of the MPI statements. If you are looking for a way to compile and run MPI on a Windows machine see this website http://curveto.com/blog/2008/03/mpich2-under-windows-vista.html. The way that the service (mpd) is run and setup is different than what I have seen in Linux but the code that it can run should be the same.
Travis is correct that there is no difference in calling MPI programs on Windows then on Linux. You might encounter general Linux to Windows porting issues is you are using system calls, but in general, Fortran applications only need a recompile or minor changes.