I need to replace hundreds of part numbers with new part numbers (migrating
to a new inventory system). These part numbers appear on about 120 different
Excel workbooks, each of which is a different order form. Any single order
form/workbook could contain 40 to 100 of the part numbers on the form. These
are usually in contiguous ranges, usually columns, but sometimes more than
one column on a spreadsheet. So, in other words, the layout is not
consistent from workbook/form to workbook/form.

I am looking for a way to replace all of the old part numbers with the new
part numbers. I already have a table of the old part numbers with the new
part numbers next to them. In a simpler scenario, I can envision using
HLOOKUP or VLOOKUP to find the number, but I don't know how to (1) replace
the existing number, or (2) continuously search the workbook for the old part
numbers and replace them with the new part numbers until it finds them all.

Any ideas of where to start with this? Thank you very much in advance.

Steve Vincent