When entering an alpha-numeric value into a cell such as 5E100, Excel
automatically converts this to the scientific numeric value. I know that this
can be over-ridden by placing an ' before the text, though I need to upload
the Excel file into a software programme and the ' is causing a problem.

Is there anyway to just have the alpha-numeric entry, but somehow 'fudge'
the format to ensure that it does not deafult to the scientific format. When
changing the format of the cell, it does not seem to revert back to 5E100,
regardless of the format.