(1) Open Visual Studio
(2) Create a window service with any name
(3) Now write your logic there
(4) Build. If successfully build
(5) Now on service file (service1.cs designer), right click and select "Add Installer" It will add "serviceProcessInstaller1" and "serviceInstaller1"
(6) Add description/name/service name
(7) Now select the properties of "serviceProcessInstaller1" and set Account=LocalSystem. If you will not select this then it will ask local system username and password every time.
(8) Mention StartType as 'Automatic'. If select 'Manual' it needs to start manually.
(9) Build this service. If its successfully build. the go on next step.
(10) Go to Visual Studio command prompt. Write there

C:\Program Files\Microsoft Visual Studio 8\VC>installutil -i "C:\Inetpub\wwwroot\ServiceName\bin\Debug\Service.exe"

If you want to uninstall window service the just write the -u instead of -i.

C:\Program Files\Microsoft Visual Studio 8\VC>installutil -u "C:\Inetpub\wwwroot\ServiceName\bin\Debug\Service.exe"

If starttype is manual, then it needs to run manually. Every time it install. It need to start manually from servies. To Start it . Go to Run > Services.msc. Right click on service and click Start.