comparing lists

Car Example
There is a list of components used in the assembly of a car along with the quantity of each component used. The car got new snow tires and a different version of a drive shaft. So the component list changed and so did the quantity of certain components such as bolts. I am left with two lists. One that correlates to the old car and one that correlates to the new car.

I want to be able to copy and paste the list of old components into a column, the list of old quantities right next to it and then do the same with the new list on the same excel sheet. I then want to copy this information to a different sheet which will then compare the two lists. I want to know what components were omitted and added along with changes to the quantity of a part used.

Is this possible?

Note:
I have multiple cars and want to be able to do this with each car when each changes. So I want to be able to copy of the data from the first sheet to the second sheet only if there is a value in that box. So maybe have a loop start at a certain point in a column and cycle down the column until I don't have anymore values.

I know it's a lot of information but I just need a little guidance. This is being used for a project at work that does not have anything to do with cars...just an example.

Thank you

Maybe if you could mock up an example workbook showing us what the "car" data looks like at the start and show us your expected output through each stage it may result in some useful guidance (or even a full solution) quicker than us guessing/creating something that needs to be adapted to suit.

BSB

Sheet 1: “Enter Old list of parts”
This is where the user will paste the existing parts list. Accompanying the parts list is a “name of list” that is placed in the grey box. This is automatic and I cannot avoid having that included when I paste into excel. When pasting the new parts list, there is no “name of list” that accompanies the list. I have highlighted in different colors what the differences are between the two lists. Looking at the new list, 4 parts have been omitted, 2 parts have been added, and the quantity of two components have changed.

Sheet 2: “Comparison”
I have imported both lists so they start on the same row. In the “Changes” column I attempted to compare the two quantities in column A and D and then in columns B and E.

Goal: I want an output box or something to tell me what parts were omitted, added, or any quantity changes that are recognized in the new list.

Id also like to figure out a way for the program to only copy over data from the first sheet to the second only if there is a value in that box. I will be comparing lists of different lengths.

Yes that is correct. I just want to see how the changes made to the old list that now creates the new list. omitted items, added, items and items that have a quantity change