Конечно, вы можете!
В свойствах вашего проекта установите для параметра Startup Object значение Sub Main и убедитесь, что в вашем приложении есть метод Public Sub Main. Хорошим вариантом может быть отдельный класс запуска:
Public Class myStartupClass
''' <summary>
''' This is the method that will be run when the application loads,
''' because Project Properties, Startup Object is set to SubMain
''' </summary>
''' <remarks>
''' </remarks>
''' --------------------------------------------------------------------------------
Public Shared Sub Main()
'The form that we will end up showing
Dim formToShow As System.Windows.Forms.Form = Nothing
'The determiner as to which form to show
Dim myMood As String = "Happy"
'Choose the appropriate form
Select Case myMood
Case "Happy"
formToShow = New Form1
Case Else
formToShow = New Form2
End Select
'Show the form, and keep it open until it's explicitly closed.
formToShow.ShowDialog()
End Sub
End Class