Maybe something along the lines of this
Code:
Sub Testing()
Dim MainRng As Range
Dim PickedRng As Range
Dim arr As Variant
Set MainRng = Range("A10:K20")
On Error Resume Next
Set PickedRng = Application.InputBox("Use mouse to select", "TITLE HERE", Type:=8)
On Error GoTo 0
If PickedRng Is Nothing Then Exit Sub
If Application.Intersect(PickedRng, MainRng) Is Nothing Then
MsgBox "Something within rows 10 to 20 please"
Cells(1).Select
Exit Sub
End If
Set PickedRng = Application.Intersect(PickedRng, MainRng)
arr = Split(Replace(Mid(PickedRng.Address, 2), ":", ""), "$")
Range("A" & arr(1) & ":K" & arr(3)).Select
End Sub