Remove duplicates in column D

Hi,
I working with Excel 2007 and would like to remove duplicates in column D, but keep the first instant.
It has to look at column A for duplicates then look at column D and remove all the duplicates, but the first one.
I need to keep the data in the other columns (A, B, C, E ...)

Original Data
Column A Column D
CH010 DUE FROM MANAGEMENT
CH010 DUE FROM MANAGEMENT
CH010 DUE FROM MANAGEMENT
CH010 SAMMY MANAGEMENT
CH010 SAMMY MANAGEMENT
CH010 AIDAN MANAGEMENT
CH010 AIDAN MANAGEMENT
CM03 SECURE MESSAGING
CM05 SECURE MESSAGING
CM05 SAFE MESSAGING
NIM010 WEAS MODEL
XAP010 OPEN FINANCIAL
XAP010 OPEN FINANCIAL
XAP010 CLOSE FINANCIAL
XAP010 CLOSE FINANCIAL



Should look like:

Column A Column D
CH010 DUE FROM MANAGEMENT
CH010
CH010
CH010 SAMMY MANAGEMENT
CH010
CH010 AIDAN MANAGEMENT
CH010
CM03 SECURE MESSAGING
CM05 SECURE MESSAGING
CM05 SAFE MESSAGING
NIM010 WEAS MODEL
XAP010 OPEN FINANCIAL
XAP010
XAP010 CLOSE FINANCIAL
XAP010


Thanks

See attached workbook.

Thanks for your reply.
Data in column F and G are correct, but how did you do it?
Data in column G should replace data in column B.

From my original question:
Also I have data data in column B, C, E, F, G, H, I, J, K, L.. which should not be changed. The only column that would be change would be D (original question on forum).
Thanks

I used this array formula in G2: =IF(SUM(IF($B$1:B1&$A$1:A1=B2&A2,1,0))>0,"",B2) + Ctrl + Shift + Enter