Source Code

The hex code is a method of representing in a file.

Each hex pair can however be associated with an assembler code (like MOV etc)

To disassemble the code one can use Debug to generate the assembler code for you.

Run DEBUG (free wit M$) and generate the desired code.

I forgot the detail but run Debug /? for help

You need a dissassembler.
However if you are trying to modify/reverse engineer someone else's code it is probably quicker to write your own from scratch!
(Unless you have full documentation...but then you wouldn't be trying to diss-assemble the hex)
Del

(I'm willing to be shown to be wrong if anyone cares to)