What kind of timer? Are you trying to measure time? Or have something
happen after some period of time? Where do you want it to run? Inside
the application? As an external process?
You can instantiate and start a Stopwatch instance in your program's
Main() method. Any time you want to know how long it's been since the
application started, just look at the Stopwatch.Elapsed property.
If you want something else, you should probably think about writing a
question that's more specific and which describes your need without
ambiguity.
Pete