VB.Net api affects windows forms

I am creating a application in vb.net and i am using some API functions.For example : GetForegroundWindow,SetWindowPos .So my app should change the active window's size and position when clicked.But it is affecting also the system forms like taskbar , StartMenu.How can i avoid this?

<Runtime.InteropServices.DllImport("user32.dll", SetLastError:=True)> _
Private Shared Function SetWindowPos(ByVal hWnd As IntPtr, ByVal hWndInsertAfter As IntPtr, ByVal X As Integer, ByVal Y As Integer, ByVal cx As Integer, ByVal cy As Integer, ByVal uFlags As Integer) As Integer
End Function ''SETTTING THE WINDOW POSITION
<Runtime.InteropServices.DllImport("user32.dll")> _
Shared Function GetAsyncKeyState(ByVal vKey As System.Windows.Forms.Keys) As Short
End Function

<Runtime.InteropServices.DllImport("user32.dll", SetLastError:=True)> _
Private Shared Function GetForegroundWindow() As IntPtr
End Function
Private ReadOnly HWND_TOP As New IntPtr(0)
Public Const SWP_FRAMECHANGED As Integer = &H20


Dim cX As Integer, cY As Integer

Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
    cX = CInt(Windows.Forms.Cursor.Position.X.ToString())
    cY = CInt(Windows.Forms.Cursor.Position.Y.ToString())


    If GetAsyncKeyState(1) <> 0 Then
        If cX <= 10 Then
            If GetForegroundWindow() <> 1 Then
                SetWindowPos(GetForegroundWindow(), HWND_TOP, 0, 0, 100, 100, SWP_FRAMECHANGED)
            End If
        End If

    End If

End Sub