Im not sure I understand what you are asking when you say does the HD have to be already partitioned?
If you erase/format a cd-rw in nero it will not be in the incd format unless you specify.
If you burn using incd and put it into any other pc it will not be able to read it unless you have nero installed. There is also an incd reader program that you can download and install instead of using the full nero.
Nero copies any files on your system that you specify and so if you specify zip files, it will burn these very successfully.