You can start the Proxy Server on Windows in any of the following ways
On the Start menu, select Programs ⇒ Oracle Corporation ⇒ Oracle iPlanet Proxy Server4 ⇒ Start Proxy Server
Use Control Panel ⇒ Administrative Tools ⇒ Services ⇒ Oracle iPlanet Proxy Server 4 (proxy-serverid) ⇒ Start
From a command prompt, go to server-root\proxy-serverid and type startsvr.bat to start the Proxy Server.