Windows Service Problems?

Currently i am building a windows service.
1. How to make a windows service that its icon display on the task bar?
2. How to show a form when we click the icon?
3. I have problem when starting the windows service, if the service have a windows component such as notifyicon, timers etc. If i am using timers from windows component instead of system.timers.timers, the error "System.Reflection.TargetInvocationException" will come out when we start the service. Could the windows service use windows component?
4. does the "timers" is elapsed every time according to the interval or just elapse once for the first time when the timers is enabled?
Thanks...