Simplest way to restart service on a remote computer

As of Windows XP, you can use sc.exe to interact with local and remote services. Schedule a task to run a batch file similar to this:

sc \\server stop service
sc \\server start service

Make sure the task runs under a user account privileged on the target server.

psservice.exe from the Sysinternals PSTools would also be doing the job:

psservice \\server restart service

DESCRIPTION: SC is a command line program used for communicating with the NT Service Controller and services. USAGE: sc [command] [service name] ...

    The option <server> has the form "\\ServerName"
    Further help on commands can be obtained by typing: "sc [command]"
    Commands:
      query-----------Queries the status for a service, or
                      enumerates the status for types of services.
      queryex---------Queries the extended status for a service, or
                      enumerates the status for types of services.
      start-----------Starts a service.
      pause-----------Sends a PAUSE control request to a service.
      interrogate-----Sends an INTERROGATE control request to a service.
      continue--------Sends a CONTINUE control request to a service.
      stop------------Sends a STOP request to a service.
      config----------Changes the configuration of a service (persistant).
      description-----Changes the description of a service.
      failure---------Changes the actions taken by a service upon failure.
      qc--------------Queries the configuration information for a service.
      qdescription----Queries the description for a service.
      qfailure--------Queries the actions taken by a service upon failure.
      delete----------Deletes a service (from the registry).
      create----------Creates a service. (adds it to the registry).
      control---------Sends a control to a service.
      sdshow----------Displays a service's security descriptor.
      sdset-----------Sets a service's security descriptor.
      GetDisplayName--Gets the DisplayName for a service.
      GetKeyName------Gets the ServiceKeyName for a service.
      EnumDepend------Enumerates Service Dependencies.

    The following commands don't require a service name:
    sc <server> <command> <option>
      boot------------(ok | bad) Indicates whether the last boot should
                      be saved as the last-known-good boot configuration
      Lock------------Locks the Service Database
      QueryLock-------Queries the LockStatus for the SCManager Database

EXAMPLE: sc start MyService

If it doesn't require human interaction which means there will be no UI that invokes this operation and I assume it would restart at some set interval? If you have access to machine, you could just set a scheduled task to execute a batch file using good old NET STOP and NET START

net stop "DNS Client"
net start "DNS client"

or if you want to get a little more sophisticated, you could try Powershell

look at sysinternals for a variety of tools to help you achieve that goal. psService for example would restart a service on a remote machine.

I recommend the method given by doofledorfer.

If you really want to do it via a direct API call, then look at the OpenSCManager function. Below are sample functions to take a machine name and service, and stop or start them.

function ServiceStart(sMachine, sService : string) : boolean;  //start service, return TRUE if successful
var schm, schs : SC_Handle;
    ss         : TServiceStatus;
    psTemp     : PChar;
    dwChkP     : DWord;
begin
  ss.dwCurrentState := 0;
  schm := OpenSCManager(PChar(sMachine),Nil,SC_MANAGER_CONNECT);  //connect to the service control manager

  if(schm > 0)then begin // if successful...
    schs := OpenService( schm,PChar(sService),SERVICE_START or SERVICE_QUERY_STATUS);    // open service handle, start and query status
    if(schs > 0)then begin     // if successful...
      psTemp := nil;
      if (StartService(schs,0,psTemp)) and (QueryServiceStatus(schs,ss)) then
        while(SERVICE_RUNNING <> ss.dwCurrentState)do begin
          dwChkP := ss.dwCheckPoint;  //dwCheckPoint contains a value incremented periodically to report progress of a long operation.  Store it.
          Sleep(ss.dwWaitHint);  //Sleep for recommended time before checking status again
          if(not QueryServiceStatus(schs,ss))then
            break;  //couldn't check status
          if(ss.dwCheckPoint < dwChkP)then
            Break;  //if QueryServiceStatus didn't work for some reason, avoid infinite loop
        end;  //while not running
      CloseServiceHandle(schs);
    end;  //if able to get service handle
    CloseServiceHandle(schm);
  end;  //if able to get svc mgr handle
  Result := SERVICE_RUNNING = ss.dwCurrentState;  //if we were able to start it, return true
end;

function ServiceStop(sMachine, sService : string) : boolean;  //stop service, return TRUE if successful
var schm, schs : SC_Handle;
    ss         : TServiceStatus;
    dwChkP     : DWord;
begin
  schm := OpenSCManager(PChar(sMachine),nil,SC_MANAGER_CONNECT);

  if(schm > 0)then begin
    schs := OpenService(schm,PChar(sService),SERVICE_STOP or SERVICE_QUERY_STATUS);
    if(schs > 0)then begin
      if (ControlService(schs,SERVICE_CONTROL_STOP,ss)) and (QueryServiceStatus(schs,ss)) then
        while(SERVICE_STOPPED <> ss.dwCurrentState) do begin
          dwChkP := ss.dwCheckPoint;
          Sleep(ss.dwWaitHint);
          if(not QueryServiceStatus(schs,ss))then
            Break;

          if(ss.dwCheckPoint < dwChkP)then
            Break;
        end;  //while
      CloseServiceHandle(schs);
    end;  //if able to get svc handle
    CloseServiceHandle(schm);
  end;  //if able to get svc mgr handle
  Result := SERVICE_STOPPED = ss.dwCurrentState;
end;

1. open service control manager database using openscmanager
2. get dependent service using EnumDependService()
3. Stop all dependent services using ChangeConfig() sending STOP signal to this function if they are started
4. stop actual service
5. Get all Services dependencies of a service
6. Start all services dependencies using StartService() if they are stopped
7. Start actual service

Thus your service is restarted taking care all dependencies.

This is what I do when I have restart a service remotely with different account

Open a CMD with different login

runas /noprofile /user:DOMAIN\USERNAME cmd

Use SC to stop and start

sc \\SERVERNAME query Tomcat8
sc \\SERVERNAME stop Tomcat8
sc \\SERVERNAME start Tomcat8

If you attempting to do this on a server on different domain you will need to a little bit more than what has been suggested by most answers so far, this is what I use to accomplish this:

#Configuration
$servername = "ABC",
$serviceAccountUsername = "XYZ",
$serviceAccountPassword = "XXX"

#Establish connection
try {
    if (-not ([System.IO.Directory]::Exists('\\' + $servername))) {
        net use \\$servername /user:$serviceAccountUsername $serviceAccountPassword
    }
}
catch {
    #May already exists, if so just continue
    Write-Output $_.Exception.Message
}

#Restart Service
sc.exe \\$servername stop "ServiceNameHere"
sc.exe \\$servername start "ServiceNameHere"