Topic may seem very old as year 2000 has passed and all computers are now year 2000 ready.

But before you can take rest here is the list of some other problems:-

Most programs written in the C programming language are relatively immune to the Y2K problem, but suffer instead from the Year 2038 problem. Unix Time stamp will expire on that day as well.
IBM PC hardware suffers from the Year 2116 problem. For a PC, the beginning of time starts at January 1, 1980, and increments by seconds. By 2116, the integer overflows.
Windows NT have a Year 2184 problem.

Good thing is that it will not be major problem as year 2000.

Well-written programs can simply be recompiled with a new version of the library that uses large byte values for storing values
because the library encapsulates the whole time activity with its own time types and functions.

Well I am worried about my own php applications, will they run after 2038? My mind is getting a naughty answer, it says, “Who will need your applications in their present structure after 34 year.”