Macro Loop Not Using All Rows

I've taken over a spreadsheet that has a macro in it. However it doesn't seen to function properly. The big issue with the Macro is that it is only running for the first 80 lines of data. I can't have a restricted range as the number of lines could increase/decrease each month depending on activity. I've attached the code.

Sub Macro1()
Dim strTemp As String
Dim intSpace As Integer
Dim intZero As Integer
Dim i As Integer
Dim strCat As String
Dim strZero As String
Dim intLoopCounter As Integer
Dim rw, this
intLoopCounter = 1
For Each rw In Worksheets(1).Cells(1, 1). CurrentRegion.Rows
this = rw.Cells(1, 1).Value ...................