Stop Idle Time Out & Log off; Win XP SP3

Hello, want my, WIN.XP SP3 Compaq/HP DeskTop, to stay logged in. Not time out, after "X" number of minutes idle. Before adding a user it left me LOGGED ON 24/7, with the screen saver showing the "My Pictures" random slide show of the thousands of family photos. Tried setting the screen saver time to start before the time out log off...But to no avail. ANY HELP OUT THERE??? Maybe restart and go into set up??

Thanks, Tom