update macro at master sheet from other sheet but no duplicate allow

[ahbag]

Hi
how to make macro for autoupdate/update but will check for duplicate.

I got 3 worksheet: master , in and out
i need to update or autoupdate what ever i add to sheet in and out to sheet master
the button will be at master.

i see many previous post is base on copy data but no post i found base on copy paste and not allow duplicate.

below is my requirement

The condition is
user will key in the data at sheet in
if no data existing, it will copy and paste(update) the new add data from sheet in to sheet master
else if there is existing data, the value that will pass is the qty from in sheet and pop up message say that "data already there" and tell the row of data exist
Be remember that column for sheet master is not the same as column for sheet in and out
Row 2 and 15 already have some data
so the macro should be able to see in this master if there have duplicate data
if no data, it will update to the last row (here is row 16) and so on

that’s is my requirement

attach is my example and some instruction

i realy need help as this is for my new jobs requirement and time consuming
thanks
hatim

[ahbag]

for additional idea, this post is quite same but the duplicate function does not include

http://www.excelforum.com/excel-new-...ter-sheet.html

thanks
hatim