VB to activate list drop-down boxes when data is entered in a cell

Hello all.
I have a Validation drop down box (column B) and a defined range drop down box (column E linked to the Totals tab with A2-A31 defined as Products) that I need to activate everytime data is added to a new line in column 'A' and cells in column 'B' or 'E' are selected. Additionally, they need to activate if the cells in column 'B' or 'E' are selected for any of the old data so changes can be made. This will help reduce the overall file size and calculation time for a year's worth of data.

There is already some code on the worksheet that looks like it can be adapted if someone knows how to code in the drop down boxes.

Thanks in advance for your assistance!!!

Andrew