i have one windows form application in v s 2010. i want to maintain a FLAG in Which there is two values of FLAG

1) yes and 2) no

i want that when a form is load a Flag value is yes and The form is close the flag value is no in my back end Database

It is same like sing in person on any web site.....

But my Problem is that How Can i manatian it any how the my computer is turn off ....... i store a database on single computer that is server.but i also want a code for on same computer,also