Help revising code. (Scrolling x Pixels per second in a rich text box)

[DllImport("user32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        static extern bool GetScrollInfo(IntPtr hwnd, int fnBar, ref SCROLLINFO lpsi);

        [DllImport("user32.dll")]
        static extern int SetScrollInfo(IntPtr hwnd, int fnBar, [In] ref SCROLLINFO lpsi, bool fRedraw);

        [DllImport("User32.dll", CharSet = CharSet.Auto, EntryPoint = "SendMessage")]
        static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

        [DllImport("user32.dll")]
        private static extern int FindWindow(string className, string windowText);

        [DllImport("user32.dll")]
        private static extern int ShowWindow(int hwnd, int command);

        private const int SW_HIDE = 0;
        private const int SW_SHOW = 1;

        struct SCROLLINFO
        {
            public uint cbSize;
            public uint fMask;
            public int nMin;
            public int nMax;
            public uint nPage;
            public int nPos;
            public int nTrackPos;
        }

        enum ScrollBarDirection
        {
            SB_HORZ = 0,
            SB_VERT = 1,
            SB_CTL = 2,
            SB_BOTH = 3
        }

        enum ScrollInfoMask
        {
            SIF_RANGE = 0x1,
            SIF_PAGE = 0x2,
            SIF_POS = 0x4,
            SIF_DISABLENOSCROLL = 0x8,
            SIF_TRACKPOS = 0x10,
            SIF_ALL = SIF_RANGE + SIF_PAGE + SIF_POS + SIF_TRACKPOS
        }

        const int WM_VSCROLL = 277;
        const int SB_LINEUP = 0;
        const int SB_LINEDOWN = 1;
        const int SB_THUMBPOSITION = 4;
        const int SB_THUMBTRACK = 5;
        const int SB_TOP = 6;
        const int SB_BOTTOM = 7;
        const int SB_ENDSCROLL = 8;

t.Interval = 30;
            t.Tick += new EventHandler(t_Tick);
            uptimer.Tick += new EventHandler(uptimer_Tick);
            uptimer.Interval = speedslider.Value * 1000;//speedslider is just a trackbar

void uptimer_Tick(object sender, EventArgs e)
        {

            scroll(telep.Handle, (speedslider.Value));
        }

private void scroll(IntPtr handle, int pixels)
        {

            {
                IntPtr ptrLparam = new IntPtr(0);
                IntPtr ptrWparam;

                SCROLLINFO si = new SCROLLINFO();
                si.cbSize = (uint)Marshal.SizeOf(si);
                si.fMask = (uint)ScrollInfoMask.SIF_ALL;
                GetScrollInfo(handle, (int)ScrollBarDirection.SB_VERT, ref si);

                {
                    if (si.nPos > (si.nMin))
                        si.nPos -= pixels;
                    else
                    {
                        ptrWparam = new IntPtr(SB_ENDSCROLL);
                        uptimer.Stop();
                        pictureBox5.Visible = true;
                        pictureBox1.Visible = true;
                        toolStripStatusLabel1.Text = "Teleprompter";
                        SendMessage(handle, WM_VSCROLL, ptrWparam, ptrLparam);
                    }
                }
                SetScrollInfo(handle, (int)ScrollBarDirection.SB_VERT, ref si, true);
                ptrWparam = new IntPtr(SB_THUMBTRACK + 0x10000 * si.nPos);
                SendMessage(handle, WM_VSCROLL, ptrWparam, ptrLparam);
            }
        }