I have a worksheet with 15 columns, one of the columns contains Part Numbers
and another column contains the cost of the associated PN. I need to update
the cost information based on a worksheet received weekly from costing. This
new worksheet only has 4 columns with updated costs, but only for PNs that
have new cost. How do I update worksheet "A" with the data from "B" without
having to search some 3000 rows?

example:
wks"A":
colA colD colE
A231 $45 apples
A452 $35 pears
B789 $23 bananas


wks"B"

A452 $32