FIND a value in a Workbook

Hello,

I'm writing a macro, in part of the macro I'm trying to search for values that are present in one workbook (lets call it Workbook A) and looking for the value in other workbook (Workbook B). The each value is present on a different tab of Workbook B. I want the sheet that is present to be activiated and then I am searching through a column for a variable I have called ColumnHeading. My current attempt looks something like this:

If Cells.Find(What:=Cusip(n), After:=ActiveCell, LookIn:=xlValues, LookAt _
:=xlPart, SearchOrder:=xlByRows, SearchDirection:=xlNext, MatchCase:= _
False, SearchFormat:=False).Found = True Then
k = 0
Do
Windows(DocMain).Activate
ActiveWorkbook.Sheets(Cusip(n)).Select
ActiveWorkbook.Sheets(Cusip(n)).Tab.ColorIndex = 3
k = k+1
Loop While (ActiveSheet.Columns(2).Cells(k) <> ColumnHeading)