Controlling refresh rate

Hello!
I'm a 18 year old student from Sweden. I'm fairly new to programming and just started ~6 months ago with Small Basic and then moved on to Visual Basic. I chose "making a fairly decent computer game" as a project in school. I have done a 2D game in the Windows Form Application. It works but I am interested in optimizing it. My question is: how do I control the screen refresh rate for the form?
I would like to set it to 0 Hz and then make it go back to the previous level or something along those lines.

An answer would be much appreciated! :)

Take a look at my managed game loop. It locks the framerate at 60 frames per second or whatever you so choose:

vb Code:

Option Explicit
 
Private Declare Function QueryPerformanceCounter Lib "kernel32" (lpPerformanceCount As Currency) As Long
Private Declare Function QueryPerformanceFrequency Lib "kernel32" (lpFrequency As Currency) As Long
 
Private Ticks_Per_Second As Currency
Private Start_Time As Currency
Private Milliseconds As Long
Private Last_Time As Long
 
Private Get_Frames_Per_Second As Long
Private Frame_Count As Long
 
Private Running As Boolean
 
Public Function Hi_Res_Timer_Initialize() As Boolean
 
    If QueryPerformanceFrequency(Ticks_Per_Second) = 0 Then
        Hi_Res_Timer_Initialize = False
    Else
        QueryPerformanceCounter Start_Time
        Hi_Res_Timer_Initialize = True
    End If
 
End Function
 
Public Function Get_Elapsed_Time() As Single
    
    Dim Last_Time As Currency
    Dim Current_Time As Currency
    
    QueryPerformanceCounter Current_Time
    Get_Elapsed_Time = (Current_Time - Last_Time) / Ticks_Per_Second
    QueryPerformanceCounter Last_Time
    
End Function
 
Private Sub Lock_Framerate(Target_FPS As Long)
 
    Static Last_Time As Currency
    Dim Current_Time As Currency
    Dim FPS As Single
    
    Do
        QueryPerformanceCounter Current_Time
        FPS = Ticks_Per_Second / (Current_Time - Last_Time)
    Loop While (FPS > Target_FPS)
    
    QueryPerformanceCounter Last_Time
 
End Sub
 
Private Function Get_FPS() As String
 
    Frame_Count = Frame_Count + 1
        
    If Get_Elapsed_Time - Milliseconds >= 1 Then
        Get_Frames_Per_Second = Frame_Count
        Frame_Count = 0
        Milliseconds = Get_Elapsed_Time
    End If
    
    Get_FPS = "FPS: " & Get_Frames_Per_Second
 
End Function
 
Private Sub Shutdown()
 
    Running = False
    Unload Me
 
End Sub
 
Private Sub Main()
    
    With Me
        .Show
        .ScaleMode = 3
        .AutoRedraw = True
        .BackColor = RGB(0, 0, 0)
    End With
 
    Running = True
    Hi_Res_Timer_Initialize
    Milliseconds = Get_Elapsed_Time
    Main_Loop
 
End Sub
 
Private Sub Main_Loop()
 
    Do While Running = True
        
        '//Timer Code Goes Here
        Me.Caption = Get_FPS
        DoEvents
        Lock_Framerate 60
        
    Loop
 
End Sub
 
Private Sub Form_Load()
    
    Main
 
End Sub
 
Private Sub Form_KeyDown(KeyCode As Integer, Shift As Integer)
 
    If KeyCode = vbKeyEscape Then
        Shutdown
    End If
 
End Sub
 
Private Sub Form_Unload(Cancel As Integer)
 
    Shutdown
 
End Sub

Also if you ever want to, take a look at my Massive DirectX Tutorial in my signature if you wanna make your games a little more professional. I also am currently redoing the entire tutorial by improving the ones I made by a lot and slapping on a couple hundred other tutorials as well in both 2D and 3D and DirectDraw in DirectX7 - DirectX11 in VB6, VB.Net 2008, VB.Net 2010, C# 2008, C# 2010, C++ 6.0, C++ 2008, and C++ 2010. I got a website going but its still under construction along with my tutorials. Its gonna cover every aspect of DirectX nearly and have advanced topics that are difficult to find on the net.