I hesitate to answer this as I have no personal experience with the software, but you should investigate MYSTRAN which is a free NASTRAN clone. It is available already compiled for Windows. From the about section of its home page:
MYSTRAN is a general purpose finite element analysis computer program
for structures that can be modeled as linear (i.e. displacements,
forces and stresses proportional to applied load). MYSTRAN is an
acronym for "My Structural Analysis", to indicate it's usefulness in
solving a wide variety of finite element analysis problems. For anyone
familiar with the popular NASTRAN computer program developed by NASA
(National Aeronautics and Space Administration) in the 1970's and
popularized in several commercial versions since, the input to MYSTRAN
will look quite familiar. Indeed, many structural analyses modeled for
execution in NASTRAN will execute in MYSTRAN with little, or no,
modification. MYSTRAN, however, is not NASTRAN. All of the finite
element processing to obtain the global stiffness matrix (including
the finite element matrix generation routines themselves), the
reduction of the stiffness matrix to the solution set, as well as all
of the input/output routines are written in independent, modern,
Fortran 90/95 code.
The author was a member of the original NASTRAN development team and the software is free and open source released under the NASA Open Source Software Agreement. If you want to use the actual NASTRAN95 code, I'm pretty sure you'll need to have a FORTRAN compiler and compile from source.
I do recommend you consider alephzero's suggestion to pursue more modern options.