I am at a loss and on a deadline with my boss... I even got a few
Excel books but apparently the wrong ones.

I have two columns of data with part numbers, and a price. What I
want to do is paste the second column in from another worksheet so
that Excel matches up one column with the other, and if there are
"blanks" it knows to just put the part numbers next to the ones they
belong to.

Example:

A B C (B and C are pasted from
another worksheet)
PARTA PARTA $5.00
PARTC1
PARTZX PARTZX $7.00
PART07
PART5T
PARTRR PARTRR $99.00

We're talking thousands of rows. How can this be easily accomplished?