I'm assuming that the current values in column 2 are not needed and won't play into this.

1. Sort the first column - so that all the identical values are grouped together

2. Put a value of 1 at the top of the 2nd column

3. In the 2nd row of the 2nd column, use this formula:

**=IF(C2=C1,E1+1,1)**

4. In the first row of the 3rd column, use this formula

**:=IF(LEN(E1) = 3, TEXT(E1,"0"),IF(LEN(E1)=1,** "00"&E1,"0"&E1))

5. Highlight and copy the 3rd column and Paste, Special, Values into the 2nd column

6. Delete the 3rd column

That should do it.