I'm trying to use excel to create a barcode sequence, with a starting number
of "00001" using the column cell code: =Code128(A2).

All is going well, except that the first 4 digits (0000) keep getting erased
leaving me with a starting number of: 1.

Is there anything I can do to stop the program from taking away the first 4
"0"s?

Stab in the dark but try formatting the cell or column with a custom
format of 00000. (zeros)