Hi,
I think u r trying to create a checkbox on runtime and give it the name stored in variable b. if so below is the code to do it:
Private Sub Command1_Click()
Dim a As CheckBox
Dim b As String
b = "check1"
Set a = Controls.Add("VB.CheckBox", b)
With a
.Visible = True
.Caption = b
.Top = 50
.Left = 50
End With
End Sub