Excel Macro - using integers as cell referenc

OK, I've written this and I'm having some trouble. I've put the comments in the code (preceded by ****) rather than giving you a summary here. I think it's easier to follow:

Sub Tester()

Dim a As Integer
Dim x As Integer
Dim y As Integer

**** a=5 - this is the equivalent of column "E"
a = 5

**** Count active columns and then rows. The totals will pin the ends of the ranges
' Count the number of data columns in the table
totalcolumns = ActiveSheet.UsedRange.Columns.Count
' Count the number of data rows in the table
totalrows = ActiveSheet.UsedRange.Rows.Count

**** y begins at column G, and x can begin anywhere. Y = Column number, X = Row number.
For y = 7 To totalcolumns
For x = 1 To totalrows

**** Everything that I do here fails, so I've actually just written this as simply as I could. a=5, x=ActiveRow and y=ActiveColumn. If specific text is found in cells in column E (a,x) then the values in column G (and beyond) should be overwritted with what I'm directing:
If Cell a,x = "Other Non-Billable Expenses" Then
Cell y,x = 0
Else
If Cell a,x = "NON-BILLABLE DIRECT COSTS" Then
Cell y,x = Cell y,x-5 + Cell y,x-4 + Cell y,x-3 + Cell y,x-2 + Cell y,x-1
Else
If Application.IsText(a, x) = "CONTRIBUTION" Then
Cell y,x = Cell y,x-10 - Cell y,x-2
Else
If Cell a,x = "Contribution %" Then
Cell y,x = (Cell y,x-1 / Cell y,x-17) * 100
Else
If Cell a,x = "Variance" Then
Cell y,x = Cell y,x-2 - Cell y,x-1
Else
If Cell a,x = "" Then
Cell y,x = ""
Else
End If
End If
End If
End If
End If
End If

****Once it has scanned the column E for the text I want and replaced the result in Column G with the value I want I need it to move to the next row (Next X), and once it has looped through to the last row (totalrows), I want it to start over at x=1 and go to the next y (Next Column, which would be H) unless y the last column (totalcolumns)
If x = totalrows Then
Next y
x = 1
Else
If y = totalcolumns Then
End Sub
Else
Next x
End If

End Sub

****Something is horribly wrong with the group of IF's. It definitely has something to do with trying to use the integer as a part of the cell reference, but I'm not exactly sure how that works. Usually I'm combing either a column or a row only. I'm in over my head on this one, and I'm hoping that someone may have a little help for me.