A question about timer

[Guest]

I meet a strange question about the timer.My programe use a timer,and work
normally for 1 year,but suddenly the timer stop working with no error.
I can't find the reason, wrong programe ,or .net timer bug,or windows timer
bug?
I need the reason and a solution.thanks.

Programs as follow:
public class Monitor
{
private void Work(Object source, ElapsedEventArgs e)
{
try
{
timer.stop();
//some operations
}
catch(Exception ex)
{
//error deals
//write logs
}
finnally
{
timer.start();
}
}
}
When work stopped,no exception,no log.
Environment: windows server 2003 ,.net framework 1.1.
The programe is a windows service.