I need to sort a list by column "A" to take out blank rows and/or rows that
are populated with garbage that tagged along when I imported it as text.
Here is the problem (simplified for easier explanation):

Cell A1 is a part number.
Cells A2:A5 are empty
Cells B1:B5 are inventory counts of A1

This pattern repeats itself and the list is too long to manually copy Cell
A1 down to A2:A5.
Of course if I sort as it is, all the rows where A2:A5 are blank will sort
to the bottom.

How can I fill all empty cells with the value immediately above it?