Hello,

>  > ocamlopt -o test.exe test.ml
> -----------
> 'ml' is not recognized as an internal or external command,
> operable program or batch file
>
> Assembler error, input left in file....
> -------------

The "'ml' is not recognized..." message is a windows message telling
that it is trying to run the test.ml file.
You could try again after renaming ocamlopt into ocamlopt.exe (if it's
not already), windows has _some_ problems with file extensions (and I
recall seeing a few ocaml executable without .exe extension).
You can also try with quotes around "test.ml".

Good luck