Bomb Shelter/Computer scene
Spoilers......................
So, overclocking the processor speeds up the clock&date function? Back in the day, a friend and I used to overclock our computers quite often. It never sped up the clock.
The easy solution was to go into BIOS settings and change the clock there. They could have just set it for 12/31/99 11:55pm and then waited 5 minutes.