Prime Number Calculation - HELP

[geo039]

I need a SIMPLE algorithm for determining prime numbers between two values a user inputs. Any good leads for VB.Net snippet.

[Arkhel]

Sub NumerosPrimos(ByVal sender As Object, ByVal e As EventArgs) Handles _
Button1.Click

If IsNumeric(TextBox1.Text) And IsNumeric(TextBox2.Text) Then
If CInt(TextBox1.Text) < CInt(TextBox2.Text) Then


Dim x, y, z As Integer
Dim noesprimo As Integer

x = TextBox1.Text
y = TextBox2.Text



Do While x <= y
z = 2
noesprimo = 0
Do While z < x
If (x Mod z) = 0 Then
noesprimo += 1
End If
z += 1
Loop

If noesprimo = 0 Then
MsgBox(x & " es primo")
End If
x += 1
Loop

Else
MsgBox("El otro texto debe ser mayor")
End If


Else
MsgBox("NO es numero")

End If


End Sub

'Se necesita haber creado un boton y dos textbox

Saludos.