Delete Sheet Rows & Columns based on cell value

Try:

Sub DeleteRowsColumns()
    Application.ScreenUpdating = False
    Dim LastRow As Long
    LastRow = Cells.Find("*", SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row
    Dim lColumn As Long
    lColumn = ActiveSheet.Cells(1, Columns.Count).End(xlToLeft).Column
    Rows(Range("A:A").Find("x").Row + 1 & ":" & LastRow).EntireRow.Delete
    Range(Cells(1, Rows(1).Find("y").Column + 1), Cells(1, lColumn)).EntireColumn.Delete
    Application.ScreenUpdating = True
End Sub

The problem of not deleting all the columns may be due to the fact that you may not have column headers in all the columns to the right of the "y". This macro should take care of that:

Sub DeleteRowsColumns()
    Application.ScreenUpdating = False
    Dim LastRow As Long
    LastRow = Cells.Find("*", SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row
    Dim lColumn As Long
    lColumn = ActiveSheet.UsedRange.Columns.Count
    Rows(Range("A:A").Find("x").Row + 1 & ":" & LastRow).EntireRow.Delete
    Range(Cells(1, Rows(1).Find("y").Column + 1), Cells(1, lColumn)).EntireColumn.Delete
    Application.ScreenUpdating = True
End Sub

Do you want to run the macro on all sheets or just some? If you want to run it only on some sheets, then I would need to know the names of those sheets and/or the names of the sheets you want to exclude.

Give this a try:

Sub DeleteRowsColumns()
    Application.ScreenUpdating = False
    Dim ws As Worksheet
    Dim LastRow As Long
    Dim lColumn As Long
    For Each ws In Sheets
        If ws.Name <> "Control" Then
            LastRow = ws.Cells.Find("*", SearchOrder:=xlByRows, SearchDirection:=xlPrevious).Row
            lColumn = ws.UsedRange.Columns.Count
            ws.Rows(ws.Range("A:A").Find("x").Row + 1 & ":" & LastRow).EntireRow.Delete
            ws.Range(ws.Cells(1, ws.Rows(1).Find("y").Column + 1), ws.Cells(1, lColumn)).EntireColumn.Delete
        End If
    Next ws
    Application.ScreenUpdating = True
End Sub

You are very welcome.