Solved: excel help if field is blank copy contents

Hi, I need help with a macro. I want to copy the contents of the cell above into the cell below if the cell below is blank.

A1 1234
B1
C1 5678
D1
E1 2345
F1
etc.

so it looks like this after the macro runs.

A1 1234
B1 1234
C1 5678
D1 5678
E1 2345
F1 2345
etc.

A1 is line 1 of column A. My apologies that I don't know how to copy an excel into my post.

Thanks in advance for your help.