How to automate, convert single column of data into two columns of data?

[Dale Saukerson]

Customer provides an Excel file that contains 1000s of keycodes in a single column.
The keycodes are not sequential. They are 16 alpha numerica characters with hyphens every four characters.
It's just a long list of keycodes.
I convert this into a text file for feeding an industrial disc (CD) printer. This is easy.
The printer spits discs one at a time, onto spindles that hold 100 discs, rotate for empty spindle, till it runs out of keycodes.

I also print the customer's file onto paper.
I massage the file to print in two columns of 50 codes each.
I use this report to spot check the output of the disc printer against the customer's file.
The report is exactly 100 codes per page.
I check the first and last (100th) disc of each spindle.

I cut and paste from client file into my file and adjust page breaks to get 100 codes per page.
I also add two columns so I can add a numbering sequence for the codes.
This is laborious when done by hand.

How can I best automate this process?

Two attachments are examples of what I do.