Option Explicit

Sub HideRowsContainingValue()
'Description: This macro will loop through a col and
'hide the row if the cell in Col A does not the value of A1.
    
Dim c As Range
Application.ScreenUpdating = False
    For Each c In Range("A2:A100").Cells
        If c.Value < Range("A1").Value Then
            c.EntireRow.Hidden = True
        End If
    Next c
Application.ScreenUpdating = True

End Sub

Sub UnhideAllColumns()
'This macro will unhide all the columns in the
'specified range.
Application.ScreenUpdating = False

    Range("A1:A100").EntireRow.Hidden = False

Application.ScreenUpdating = True
End Sub