Prevent the system from entering standby mode if there are active downloads, certain applications are running, or if the resource usage is higher than the thresholds you set.
http://stand-bye.chillsoft.de/en/index.html
http://www.softpedia.com/get/System/Launchers-Shutdown-Tools/Stand-Bye.shtml
http://stand-bye.chillsoft.de/en/index.html
http://www.softpedia.com/get/System/Launchers-Shutdown-Tools/Stand-Bye.shtml