when the user log on(switch on) the system Capturing a Desktop screen until the user log off(shutdown) the system using Windows services?

Hello,
yes you can do like this 
you need to do two things
first create a window service that track window is start or not
when system login or start then you window service start with boot
then your application also start with window boot then window service send you notification to window is ready to take a snap of screen 
then your window app can take a snap or screen but your window app not show in process or task bar its should be hide if you make a better software or hide software i guess you need same like this


Thanks
Dharmesh sharma
www.dharmeshsharma.com