Sort and match whole columns' data?

Hi, everyone, i am an excel beginner, i now have an excel that contains 3 columns that column B and column C are matched already.(below)

A B C
1 4 4.1
2 5 5.1
3 6 6.1
7 1 1.1
2 2.1
3 3.1

how to change to that as follows? (below)
A B C
1 1 1.1
2 2 2.1
3 3 3.1
NIL 4 4.1
NIL 5 5.1
NIL 6 6.1
7 NIL NIL

i want the smallest number should be at the top, and if A and B are not matched, Nil will be shown.
Thanks everyone....better to provide me the steps and method/code.

Hi

This works with your sample data, assuming it is in the range A1:C6.

However, if your real data is likely to contain a number in column A that doesn't have a match in column B, then it will have to be revised.

Sub aaa()
'sort columns B and C based on column B
  Range("B:C").Sort order1:=xlAscending, key1:=Range("B1")
'step through the data in column A, and if the number is > than the number
'in column B, then shift it down.
  For i = 1 To Cells(Rows.Count, 2).End(xlUp).Row
    If Cells(i, 1) > Cells(i, 2) Then Cells(i, 1).Insert shift:=xlDown
  Next i
End Sub

rylo