Help compiling a program using g77

[Enrique Farfan]

I am interested in compile a program using g77. The program was wrote in
fortran and compiled with a fortran compaq compiler. I have been working
in it changing some stuffs in the original program but I have one
problem after another. I don't know how much compatibility exist between
the fortran compaq compiler and g77. Anyway I need some help.

Thanks

Enrique