<pre class="prettyprint" style="width: 581px; height: 341px;">Dim mess_tex As String
Dim dir_url As String
Sub Botón1_Haga_clic_en()
dir_url = "
http://www.todoexpertos.com/"
open_web
End Sub
Sub Botón2_Haga_clic_en()
dir_url = "
https://login.live.com/login.srf?wa=wsignin1.0&rpsnv=12&ct=1395122041&rver=6.4.6456.0&wp=MBI&wreply=http:%2F%2Fmail.live.com%2Fdefault.aspx&lc=12298&id=64855&mkt=es-ec&cbcxt=mai&snsc=1"
open_web
End Sub
Sub Botón3_Haga_clic_en()
dir_url = "
https://accounts.google.com/ServiceLogin?service=mail&passive=true&rm=false&continue=http://mail.google.com/mail/&scc=1<mpl=default<mplcache=2&emr=1"
open_web
End Sub
Sub Botón4_Haga_clic_en()
dir_url = "
https://www.facebook.com/"
open_web
End Sub
Private Sub open_web()
Dim shell_w As ShellWindows
Dim IntExp As InternetExplorer
Dim idx As Long, pw_count As Long
Set shell_w = New ShellWindows
idx = 0
pw_count = 0
If shell_w.Count > 0 Then
For idx = 0 To shell_w.Count - 1
If shell_w.Item(idx).LocationURL = dir_url Then
pw_count = pw_count + 1
End If
Next
If pw_count > 0 Then
Set IntExp = shell_w.Item(0)
mess_text = dir_url & "--> Ya está abierta"
MsgBox (mess_text)
Else
Set IntExp = New InternetExplorer
IntExp.Navigate (dir_url)
IntExp.Visible = True
End If
Else
Set IntExp = New InternetExplorer
IntExp.Navigate (dir_url)
IntExp.Visible = True
End If
Set shell_w = Nothing
Set IntExp = Nothing
End Sub</pre>
Hola primero crea 4 commanbuttoms que hagan referencia a cada función.
Si te sirvió la solución por favor califica y cierra la pregunta