If you were to start out with all cells on the sheet unlocked then you
could use a worksheet change event similar to this. This checks entry in
columm A and then locks columns C,D and E on that row:

Private Sub Worksheet_Change(ByVal Target As Range)
If Target.Count = 1 And Target.Column = 1 _
And Target.Value = "x" Then
Me.Unprotect Password:="mypassword"
Range(Cells(Target.Row, 3), Cells(Target.Row, 5)).Locked = True
Me.Protect Password:="mypassword"
End If
End Sub

Hope this helps
Rowan

Gary Keramidas wrote:
what would be the best way to do this:

if an x is entered in a cell, lock a range of cells in that same row so
nothing in that range could be entered?