Writing Data To a 64 Based Game

I come from console modding and now that I have some knowledge I want to modify dead games.

So whilst attempting to send bytes to the program, I receive the the following error "System.OverflowException: 'Value was either too large or too small for a UInt32.'"

So I need to use something like ulong or long but I've no idea on how to implement it.

I would also like to use bytes instead, for example:

pc.writeMemory("0x140B1CE16", //byte 0x44);

example code 1:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Diagnostics;
using System.Runtime.InteropServices;
using System.Threading;
using ReadWriteMemory;

namespace AW
{
    public partial class Form1 : Form
    {

        Process[] processname;

        public static UInt64
            TamperProtection = 0x140B1CE16;
        public Form1()
        {
            InitializeComponent();
        }

        [DllImport("kernel32.dll")]
        static extern IntPtr OpenProcess(UInt64 dwDesiredAccess, bool bInheritHandle, Int64 dwProcessId);
        [DllImport("kernel32.dll")]
        private static unsafe extern Boolean WriteProcessMemory(IntPtr hProcess, IntPtr lpBaseAddress, byte[] lpBuffer, int nSize, void* lpNumberOfBytesWritten);
        [DllImport("kernel32.dll")]
        static extern Int64 CloseHandle(IntPtr hObject);

        static public IntPtr MemoryOpen(Int64 ProcessID)
        {
            IntPtr hProcess = OpenProcess(0x1F0FFF, false, ProcessID);
            return hProcess;
        }
        unsafe public void Write(UInt64 mAddress, byte[] Buffer, Int64 ProcessID)
        {
            if (MemoryOpen(ProcessID) == (IntPtr)0x00000000)
            {
                return;
            }
            if (!WriteProcessMemory(MemoryOpen(ProcessID), (IntPtr)mAddress, Buffer, Buffer.Length, null))
            {
                return;
            }


        }

        private void button1_Click(object sender, EventArgs e)
        {
            processname = Process.GetProcessesByName("s1_mp64_ship");
            if (processname.Length == 0)
            {
                MessageBox.Show("The game process was not detected!\nPlease open the game.", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            }
            else
            {
                MessageBox.Show("Connected!", "Connection Sucessfull", MessageBoxButtons.OK, MessageBoxIcon.Information);
            }
        }

        private void button2_Click(object sender, EventArgs e)
        {

        }

        private void button3_Click(object sender, EventArgs e)
        {
            processname = Process.GetProcessesByName("s1_mp64_ship");
            int Value = 0;
            byte[] Buffer = BitConverter.GetBytes(Convert.ToInt32(Value));
            Write(5380360708U, Buffer, processname[0].Id);
            CloseHandle(MemoryOpen(processname[0].Id));
        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}

and here is example code 2:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Diagnostics;
using System.Threading;
using Memory;


namespace Anubis
{
    public partial class Form1 : Form
    {
        Mem pc = new Mem();
        public Form1()
        {
            InitializeComponent();
        }

        private void button11_Click(object sender, EventArgs e)
        {
            CallingCard f2 = new CallingCard();
            f2.ShowDialog(); // Shows Form2
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            pc.OpenProcess("s1_mp64_ship");

        }

        private void button12_Click(object sender, EventArgs e)
        {
            PublicMatchClasses f3 = new PublicMatchClasses();
            f3.ShowDialog(); // Shows Form2
        }

        private void button13_Click(object sender, EventArgs e)
        {
            PrivateMatchEditor f4 = new PrivateMatchEditor();
            f4.ShowDialog(); // Shows Form2
        }

        private void button1_Click(object sender, EventArgs e)
        {
            pc.writeMemory("0x140B1CE16", "int", "2"); 
        }
    }
}