After configured my system settings and preferences I restarted the laptop the all settings that i have configured like system mouse and touchpad setting, Wi-Fi password and system preference , gets defaults , system setting changes are not persist.
First of all, this is an installed system I guess, not a live USB (which are not persistent), right?
Maybe you could provide your detail specs via
Are you sure the settings and subsequent restart were done with the same user? Did you happen to use guest?
Any important updates made in between?
As @filo already mentioned, it is likely you logged in on the guest account. Settings do not persist when using a guest account.