if i had to guess and be pretty much right, that looks like ALL the batteries need to be replaced.
there is a battery in the computer, and a battery on the IO board (next to the itouch9 button key).
the computer will be a regular CR2032 battery. be sure to properly set the date and time in the bios to make sure the game operates properly. it's a bit of a pain to get in and out, as the cords and plugs are really short
the IO board has a 3 volt LiSOCL2 (Lithium Thionyl Chloride) battery. it's most often called a "CR 1/2 AA" or a "LS14250" or even "CR14250SL". the one on there is likely a purple/black/green "Tadiran" brand battery or a white/green "Saft" brand battery. best to try and find a place that specifically sells batteries... because you will need one with wires or solder tabs welded onto it, as they often come with nothing attached and soldering directly to a battery is really bad for it. you will need to de-solder and solder in a new one. often battery places will swap a battery like this for you for a fee if you don't want to mess up your board.
once you get the batteries replaced, you'll run into the corrupted data/reset thing again, but now once the defaults are loaded up, it'll keep them in memory now and it will boot up normally the next time without the message.