To get the POV-Ray v3.1g executable for MS-Dos -

  o download povmsdos.exe.
  o run it in a temporary directory.
  o run the install.exe program produced.
  o follow the instructions.

To get the POV-Ray source code in C for MS-Dos -

  o get the executable and install as shown above
  o get povmsd_s.zip and unzip -d in your \povray3
    directory.
  o read compile.doc and other docs

Note: Source isn't necessary just to run the program.