How do I reassemble a zip file that has been emailed in multiple parts?

It's fairly safe to assume that the file parts just need to be concatenated together.

The easiest way to do this is within 7-Zip - navigate to the folder in the 7-Zip file manager, right-click on the first file in the sequence, and select "Combine Files..." from the context menu.

It can also be easily done on the command line.

On Windows:

copy /B input.z* output.zip

Or Linux (or if you've got Unix command line tools on Windows using Cygwin or GnuWin32):

cat input.z* > output.zip

Usually there is one *.zip in the set and a couple of *.z??. If you open the *.zip the others are unziped as well as long as they are in the same directory.

If this does not work try what therefromhere said, or if you are on windows:

copy /B yourfile.z00 + yourfile.z01 + yourfile.z02 yourfile.zip

Have you tried to unzip all the files? Usually, one have to unzip just one (the first or the last). Maybe, if you change the extesion of the .z00 to .zip, will be able to unzip all.