Y2K refers to the Year 2000 and sometimes specifically to the Year 2000 computer bug. The Year 2000 computer bug was causing a lot of worry to computer companies leading up to the year 2000. The reason for this was that computer companies were not sure how the date handling functions of computer programs would handle the change to 2000. Due to the updating of programs leading up to the year 2000 and general hype in the world press the actual Y2K bug caused few problems.