Need Help on Lookup function

[David]

I have a table as below in my 2nd worksheet:
Part No. Location Qty
AAA T65 1
AAA T65 2
AAA T77 5
BBB T65 3
BBB T65 5
CCC T77 6
DDD T77 7

In my first worksheet I have column A populated with my Part No.:
A B C
1 AAA
2 BBB
3 CCC
4 DDD
5 EEE

I would appreciate very much if some one is kind enough to guide me on how
to to a VBA in column C. Can I do a combox box data validation on column
C? If user click on row 1, column 'C' combo box, then I need the combo to
display a list as shown below:

AAA T65 1
AAA T65 2
AAA T77 5

Ideally all the 3 rows information above should be inside a combo box or a
comments box.

TIA,

Best regards
CT