Speed up camparing two workbooks VBA

[Helidragon]

Help Please, this code is taking to long to complete. I believe because of the two Loops, each loop contains 100 cells so it is looping through 10000 cells and taking about 6 mins to complete. My guess is there is another way to do this and not take so long. Any help would be appreciated.

Private Sub CommandButton1_Click()
Dim c, c2, SN, FLexBn, FlexNN As Range
Dim Flex As Workbook
Dim wks As Worksheets


Set SN = Worksheets((MonthName(Month(Range("Date")))))
Set RngAN = SN.Range("DLCAN11")
Set AN = Range("1:24").Find("Acct. No.", , , xlWhole, , , False, , False)
Set Flex = Workbooks.Open("c:\Flex 123\Monitored Line (Flex 123) Report.xlsx")
Set RLC = ThisWorkbook

    For Each c In RngAN
         If c.Value <> "" And c.Value <> "Days Past Due" Then
            With Flex
                For Each c2 In Worksheets("page1").Range("c4:c100")
                    If c2.Value = c.Value Then
                        c2.Interior.ColorIndex = 38
                    End If
                Next c2
        
            End With
         End If
    Next
 
    For Each c2 In Flex.Worksheets("page1").Range("c4:c100")
        With Flex
            For Each c In RngAN
                If c.Value = c2.Value And c.Value <> "Days Past Due" Then
                    If c.Offset(0, -1).Value <> c2.Offset(0, 1).Value Then
                       c.Offset(0, -1).Interior.ColorIndex = 38
                       c.Offset(0, -1).Value = c2.Offset(0, 1).Value
                    End If
                    If c.Offset(0, 2).Value <> c2.Offset(0, 5).Value Then
                       c.Offset(0, 2).Interior.ColorIndex = 38
                       c.Offset(0, 2).Value = c2.Offset(0, 5).Value
                    End If
                    If c.Offset(0, 8).Value <> c2.Offset(0, 6).Value Then
                       c.Offset(0, 8).Interior.ColorIndex = 38
                       c.Offset(0, 8).Value = c2.Offset(0, 6).Value
                    End If
                    If c.Offset(0, 7).Value <> c2.Offset(0, 7).Value Then
                       c.Offset(0, 7).Interior.ColorIndex = 38
                       c.Offset(0, 7).Value = c2.Offset(0, 7).Value
                    End If
                    If c.Offset(0, 6).Value <> c2.Offset(0, 8).Value Then
                       c.Offset(0, 6).Interior.ColorIndex = 38
                       c.Offset(0, 6).Value = c2.Offset(0, 8).Value
                    End If

                End If

            Next c
    
        End With
    Next
 
 End Sub

 

[Helidragon]

Thank you everyone for the help. I started changing it but it will take me a few days to try each idea and work through the kinks of not knowing what I’m doing. ?