Processes on my machine...

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Diagnostics;

namespace TestOne
{
    class Program
    {
        static void Main(string[] args)
        {
            EnumMods(0);
            Console.ReadKey();
        }

        static void EnumMods(int PID)
        {
            Process theProc = null;
            try
            {
                theProc = Process.GetProcessById(PID);
            }
            catch (ArgumentException ex) { 
                Console.WriteLine(ex.Message);
                return;
            }
            Console.WriteLine("Here are the loaded modules for: {0}", theProc.ProcessName);
            ProcessModuleCollection theMods = theProc.Modules;
            foreach (ProcessModule pm in theMods)
            {
                String info = string.Format("-> Mod Name: {0}", pm.ModuleName);
                Console.WriteLine(info);
            }
        }
    }
}

Error
Here are the loaded modules for: Idle
 
Unhandled Exception: System.ComponentModel.Win32Exception: Unable to enumerate t
he process modules.
at System.Diagnostics.NtProcessManager.GetModuleInfos(Int32 processId, Boolea
n firstModuleOnly)
at System.Diagnostics.ProcessManager.GetModuleInfos(Int32 processId)
at System.Diagnostics.Process.get_Modules()
at TestOne.Program.EnumMods(Int32 PID) in c:\users\slyth_000\documents\visual
studio 2010\Projects\TestOne\TestOne\Program.cs:line 29
at TestOne.Program.Main(String[] args) in c:\users\slyth_000\documents\visual
studio 2010\Projects\TestOne\TestOne\Program.cs:line 13
Press any key to continue . . .