cannot started service after deploy http.sys application

[Stéphane]

i made a mistake when i deploy the exe : it is necessary to use "ApplicationName.exe /install" in cmd running as adminiatrator (and not "sc create ...")
well it works now !
but when i try to deploy the second exe (HttpSysDemo2.exe) i got a error message : code 1073 : the specified service already exists
why ? it's not the same application