computers LOL

The other day I realised that my laptop CMOS battery had gorn flat (I do not use it much).
Opened it up and found it was a CR2032 – we actually had a spare one in the drawer LOL – so I shoved it in its slot and refitted the keyboard.
Excellent : ) – what could possibly go wrong ??
Well the laptop decided it was 11/12/2120 – and the next auto update had become 18/12/2120 so that was useless : )
Anyway I had to hold down the manual calender adjust all the way back to 2016 – seemed to take forever (prob 5mins).