Copia este codigo
en en encabezado
Private Declare Function ShellExecute Lib "shell32.dll" Alias "ShellExecuteA" (ByVal hwnd As Long, ByVal lpOperation As String, ByVal lpFile As String, ByVal lpParameters As String, ByVal lpDirectory As String, ByVal nShowCmd As Long) As Long
Const conSwNormal = 1
Cuando deseas que se abra copia
On Error Resume Next
ShellExecute hwnd, "open", "http://www.gedzac.com ", vbNullString, vbNullString, conSwNormal
Esto te servir{a cualquier cosa me avisas, Suerte