How to restart service using command prompt

You have at least three options. I have presented them in order of usage preference.

Method 1 - You can use the SC tool (Sc.exe) included in the Resource Kit. (included with Windows 7/8)

Open a Command Prompt and enter

sc delete <service-name>

Tool help snippet follows:

DESCRIPTION:
        SC is a command line program used for communicating with the
        NT Service Controller and services.

delete----------Deletes a service (from the registry).

Method 2 - use delserv

Download and use delserv command line utility. This is a legacy tool developed for Windows 2000. In current Window XP boxes this was superseded by sc described in method 1.

Method 3 - manually delete registry entries (Note that this backfires in Windows 7/8)

Windows services are registered under the following registry key.

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services

Search for the sub-key with the service name under referred key and delete it. (and you might need to restart to remove completely the service from the Services list)

You don't need installutil.exe and probably you don't even have rights to redistribute it.

Here is the way I'm doing it in my application:

using System;
using System.Collections.Generic;
using System.Configuration.Install; 
using System.IO;
using System.Linq;
using System.Reflection; 
using System.ServiceProcess;
using System.Text;

static void Main(string[] args)
{
    if (System.Environment.UserInteractive)
    {
        string parameter = string.Concat(args);
        switch (parameter)
        {
            case "--install":
                ManagedInstallerClass.InstallHelper(new string[] { Assembly.GetExecutingAssembly().Location });
                break;
            case "--uninstall":
                ManagedInstallerClass.InstallHelper(new string[] { "/u", Assembly.GetExecutingAssembly().Location });
                break;
        }
    }
    else
    {
        ServiceBase.Run(new WindowsService());
    }
}

Basically you can have your service to install/uninstall on its own by using ManagedInstallerClass as shown in my example.

Then it's just matter of adding into your InnoSetup script something like this:

[Run]
Filename: "{app}\MYSERVICE.EXE"; Parameters: "--install"

[UninstallRun]
Filename: "{app}\MYSERVICE.EXE"; Parameters: "--uninstall"