Timer in managed Windows Service

Writing a managed Windows service be careful trying to implement any timer functionality: Timers from Forms namespace won't work - mostly

Use System.Threading.Timer instead.
A couple things to know:
1. Use the Timer constructor wisely:

public Timer(
   TimerCallback callback, // create a private void method with only stateInfo
                           // argument (the method signature is essential)
   Object state,           // can be null if you do not plan to use a sync object
   int dueTime,            // delay before first timer event gets fired
   int period              // timer event interval - what else
)

2. Use Change method to Stop/Restart the timer:

public bool Change(
   int dueTime, // set Timeout.Infinite to stop the timer or smth else to continue
   int period   // see above
)

3. Do not forget to Dispose() the timer when it is no more required

Enjoy!