dell OPITPLEX 780 computer LIGHTS

[2dogs3cats]

My dell Opitplex 780 boots up and run but will cut off after about 2 to 3 mins.
when it running good I have a light that look like a small battery that is blinking.
is this for the 3.0v battery

 

[C12Friedman]

I'll suggest replacing the 3V battery on the motherboard (most commonly a CR2032, available almost everywhere) to start with since that battery going bad can have all kinds of strange effects on the PC's operation including shutting down