Deleting Rows and Columns Throughout All Worksheets

Should be

Option Explicit

Sub Test()
    Dim SH As Worksheet
    Application.ScreenUpdating = False
        For Each SH In ThisWorkbook.Sheets
            SH.Rows("1:3").EntireRow.Delete
            SH.Columns("A:C").Delete
            SH.Cells.UnMerge
        Next
    Application.ScreenUpdating = True
End Sub

 'OR
Sub Test1()
    Dim SH As Worksheet
    Application.ScreenUpdating = False
        For Each SH In ThisWorkbook.Sheets
            With SH
              .Rows("1:3").EntireRow.Delete
              .Columns("A:C").Delete
              .Cells.UnMerge
            End With
        Next
    Application.ScreenUpdating = True
End Sub

I'm trying to delete columns A, B, and G, not C. Sorry for any confusion