A few individuals thought that there would be a catastrophic meltdown of civilization as computers all crashed and refused to work at all. The media loves disaster stories, and turned this into The Sky Is Falling. The sky was never going to fall. There was going to be no disaster.
It was mostly those old Cobol programs that were a problem. They used two digits for the year, so “00” (1900) was equal to “00” (2000). And other anomalies. Companies spent a lot of money to locate and fix problem programs. They got almost all of them, and there was no meltdown of Life as We Know it.
I was watching TV at midnight end 1999 beginning 2000 as the cameras showed Times Square and the commentator mentioned that everything seemed to be OK.
The world didn’t end, and the ones who peddled survival equipment during the scare didn’t offer a refund on the merchandise.
I told everyone my coffee pot was too stupid to care what the year was. All it knew was that at 0600 it turned itself on and brewed up the coffee.
By the the time I got in the kitchen there it was - a fresh pot of coffee.