closing program for no activity

[padobranac]

Could anybody explain me hoe could I can stop and close all program for no activity (when screensaver is activating, or after 1 minute of no activity on computer)

I want to use Ubuntu for public free (no password and no limit) and want to close program if somebody leave open firefox after 1 minute of no activity so it will back desktop page.

Thanks

[padobranac]

Anybody could help?

How could I close all program with one command and stay logged on.