I have a form which contains several fields, one of the fields is called : Has The Member Had an Assessment, This field is a yes/no field, if this field = no i want Command1 to become invisible, i have tried putting the following code on current event of the form and afterupdate on the yes no field:
If Me.Has_The_Member_Had_an_Assessment = "No" Then Me.Command1.Visible = False
If Me.Has_The_Member_Had_an_Assessment = "Yes" Then Me.Command1.Visible = True
but this is not working, please help!!

Try it without the quotes around the YES and NO in your conditions; Yes and No are constants in VBA, equivalent to True and false.

Mike