// TSTCOM.cs
//
[assembly:System.Reflection.AssemblyKeyFileAttribute(@ "oxp.tstcom.snk" )]
namespace OXP {
    using System;

    /// <summary>
    /// Summary description for TSTCOM.
    /// </summary>
    public class TSTCOM {

        /// <summary>
        /// Creates a new instance of TSTCOM
        /// </summary>
        public TSTCOM() {
        }

        public string Hello() {
            return  "Hello everybody!" ;
        }

        public int AddTwo(int a, int b) {
            return a + b;
        }

        public string Echo(string a) {
            return a.ToUpper();
        }
    }
}

REGEDIT4

[HKEY_CLASSES_ROOT\OXP.TSTCOM]
@= "OXP.TSTCOM" 

[HKEY_CLASSES_ROOT\OXP.TSTCOM\CLSID]
@= "{82F69283-9C92-3021 -ACB7-CF2D8A400F06}"

[HKEY_CLASSES_ROOT\CLSID\{82F69283-9C92- 3021 -ACB7-CF2D8A400F06}]
@= "OXP.TSTCOM" 

[HKEY_CLASSES_ROOT\CLSID\{82F69283-9C92- 3021 -ACB7-CF2D8A400F06}\InprocServer32]
@= "mscoree.dll" 
 "ThreadingModel" = "Both" 
 "Class" = "OXP.TSTCOM" 
 "Assembly" = "TSTCOM, Version=0 . 0 . 0 . 0 , Culture=neutral, PublicKeyToken=f5cd2565ac4a140f"
 "RuntimeVersion" = "v1.1 . 4322 "
 "CodeBase" = "file:///L:/a_user/Projects/OXP/TSTCOM.DLL" 

[HKEY_CLASSES_ROOT\CLSID\{82F69283-9C92- 3021 -ACB7-CF2D8A400F06}\InprocServer32\ 0 . 0 . 0 . 0 ]
 "Class" = "OXP.TSTCOM" 
 "Assembly" = "TSTCOM, Version=0 . 0 . 0 . 0 , Culture=neutral, PublicKeyToken=f5cd2565ac4a140f"
 "RuntimeVersion" = "v1.1 . 4322 "
 "CodeBase" = "file:///L:/a_user/Projects/OXP/TSTCOM.DLL" 

[HKEY_CLASSES_ROOT\CLSID\{82F69283-9C92- 3021 -ACB7-CF2D8A400F06}\ProgId]
@= "OXP.TSTCOM" 

[HKEY_CLASSES_ROOT\CLSID\{82F69283-9C92- 3021 -ACB7-CF2D8A400F06}\Implemented Categories\{62C8FE65-4EBB-45E7-B440-6E39B2CDBF29}]

o1 = CreateObject( "OXP.TSTCOM" )
?o1.Hello()
?o1.AddTwo( 1 , 2 )