I have a windows application written in VS 2005. The application makes queries against to sql database in a timer cycle every 2 minutes. If there any data changes, the window will be refreshed with new data.

If the user leaves the window, the windows will be automatically locked after a while. There is no sense to keep querying data in ever 2 minutes when the windows is locked; therefore I would like to stop the query when lock is on so that the network data trafic will be reduced and also saves the current windows resources such as memory and CPUs.

I am not sure if there is any way to find out the current windows is locked? Not sure if there is any Windows APIs for this purpose if no .Net classes available?

My project is in .Net 2.0 and all users are in Windows XP.