Well,  you can try this - totally untested, and some things in the code
you'll have to change in the "user defined" area near the beginning of it.  
To put the code into your workbook #3, open it and press [Alt]+[F11] and then
use Insert | Module to create a code module to contain it.  Copy this code
and paste it into the module, make changes to workbook/worksheet names as
needed and give it a try.  All 3 workbooks MUST be open at the same time for
it to work.  Use Tools | Macro | Macros to run it - it will request the
customer ID from you, if you leave -1 in the input box or clear the input
box, it will abort.

As I said, totally untested - if you have problems, post here.  If code
fails, choose [Debug] and see which line of code failed (it will be
highlighted).  In worst case, you can contact me at (remove spaces) HelpFrom
@ jlathamsite.com - if you do, send some sample data for me to work with.

To do an early check to see if it has any hope of running, after you copy it
in and make your changes, choose [Debug] from the VB Editor menu and then
click Compile VBA Project - it should compile without error.  If  you get an
error indication, it means either your edit messed up something or the paste
itself may have split a line where it shouldn't have been split.  If it
compiles without error, give it a test.  Make sure and work from copies of
your 2 source workbooks just to be safe.  This should be a non-destructive
process for those 2 workbooks, but if I made a typo I haven't noticed, it has
a slim chance of erasing data in the source book.

Sub CombineData()
 'all 3 workbooks must be open before calling this routine

'begin user defined values: change as required  
 Const WB1name = "Workbook1.xls"
 Const WB2name = "Workbook2.xls"
 'to hold source sheet names
 Dim WSList(1 To 4) As String
 'sequence these in the order you want
 'to bring in the data from WB1 and WB2
 'change to actual name of the sheets
 'must be the same in both source workbooks
 WSList(1) = "Customer"
 WSList(2) = "Address"
 WSList(3) = "Email"
 WSList(4) = "Phone"
 
 Const destSheetName = "Sheet1" ' sheet in this workbook for copy
'end of user defined values
 
 Dim customerID As Integer ' hold number user enters
 
 ' will be workbook WB1name
 Dim WB1 As Workbook
 ' will be workbook WB2name
 Dim WB2 As Workbook
 ' varies as we work through books WB1 & WB2
 Dim srcSheet As Worksheet
 ' will be sheet destSheetName
 Dim destSheet As Worksheet
 ' to build up addresses to assign to ranges
 Dim anyAddress As String
 'to isolate customer ID numbers for examination
 Dim custIDRange As Range
 ' to copy from
 Dim srcRange As Range
 ' to copy to
 Dim destRange As Range
 'loop counter for working through worksheets
 Dim SLC As Integer
 'to look at customer ID on other sheets
 Dim testID As Range
 'to find available row in this workbook
 Dim lastRow As Long
 'to find last used column in source data
 Dim lastCol As Long

'get the customer ID number to retrieve data for
 On Error Resume Next
 customerID = InputBox$("Enter Customer ID", "Cust.ID#", -1)
 If Err <> 0 Then
   MsgBox "Invalid entry - must be a positive integer", _
    vbOKOnly, "Quitting"
   Err.Clear
   On Error GoTo 0
   Exit Sub
 End If
 On Error GoTo 0 ' clear error trap
 If customerID <= 0 Then
   Exit Sub ' -1 is 'invalid'
 End If

 'this will fail if other workbooks aren't open
 Set WB1 = Workbooks(WB1name)
 Set WB2 = Workbooks(WB2name)
 Set destSheet = ThisWorkbook.Worksheets(destSheetName)
 'clear previous results?
 destSheet.Cells.ClearContents
 'go get data from WB1
 For SLC = LBound(WSList) To UBound(WSList)
   Set srcSheet = WB1.Worksheets(WSList(SLC))
   anyAddress = "A1:A" & _
    srcSheet.Range("A" & Rows.Count).End(xlUp).Row
   Set custIDRange = srcSheet.Range(anyAddress)
   For Each testID In custIDRange
     If testID = customerID Then
       'have match on customer ID
       'copy all cells used on the source row
       lastCol = Cells(testID.Row, Range("IV" & _
        testID.Row).End(xlToLeft).Column)
       anyAddress = "A" & testID.Row & ":" & _
        Cells(testID.Row, lastCol).Address
       Set srcRange = srcSheet.Range(anyAddress)
       'find where to put it in this workbook
       lastRow = destSheet.Range("A" & _
        Rows.Count).End(xlUp).Row + 1
       anyAddress = "A" & lastRow & ":" & _
        Cells(lastRow, lastCol).Address
       Set destRange = destSheet.Range(anyAddress)
       'do the copy
       destRange.Value = srcRange.Value
     End If
   Next ' end of test of customer ID entries
 Next ' end of SLC sheet loop for WB1
 'move to Workbook 2 and get the data from it
   
 For SLC = LBound(WSList) To UBound(WSList)
   Set srcSheet = WB2.Worksheets(WSList(SLC))
   anyAddress = "A1:A" & _
    srcSheet.Range("A" & Rows.Count).End(xlUp).Row
   Set custIDRange = srcSheet.Range(anyAddress)
   For Each testID In custIDRange
     If testID = customerID Then
       'have match on customer ID
       'copy all cells used on the source row
       lastCol = Cells(testID.Row, Range("IV" & _
        testID.Row).End(xlToLeft).Column)
       anyAddress = "A" & testID.Row & ":" & _
        Cells(testID.Row, lastCol).Address
       Set srcRange = srcSheet.Range(anyAddress)
       'find where to put it in this workbook
       lastRow = destSheet.Range("A" & _
        Rows.Count).End(xlUp).Row + 1
       anyAddress = "A" & lastRow & ":" & _
        Cells(lastRow, lastCol).Address
       Set destRange = destSheet.Range(anyAddress)
       'do the copy
       destRange.Value = srcRange.Value
     End If
   Next ' end of test of customer ID entries
 Next ' end of SLC sheet loop for WB2
 'cleanup: release resources back to the system
 Set custIDRange = Nothing
 Set destRange = Nothing
 Set srcRange = Nothing
 Set srcSheet = Nothing
 Set destSheet = Nothing
 Set WB1 = Nothing
 Set WB2 = Nothing
End Sub