Lost settings

It might have been answered before but i couldn't find it.

I am not sure what have happened but my router has lost all of its settings (DHCP reservations, SSID name, admin credentials etc) - it revereted to default SSID and i was greeted with initial setup once i've connected to it via browser.

I am wondering if anyone else have experienced this and what is the solution to avoid it doing so in the future.

My router is brand new (not 2 days have past). It's on 3.0.0.4.220.

P.S. I've noticed that it's running hot - its plastic case is hot to touch (it is not melting).

Thanks.