You could cause application and license damage that may not be reversible. Run compliance tests. Create a risk management plan, a plan on how to address emergencies that may arise, how to proceed if your fixes do not work, and what your alternatives are. Do this early, do not leave it for the last minute. Plan workarounds and backup strategies.
Nothing really happend .
Keep track of how often you use date-sensitive applications. Make sure those are Y2k compliant. This PC risk and impact assessment assumes absence of Y2k viruses, and lack of deliberate Y2k related security attacks. It also excludes the pre-existing software, hardware and failure conditions, i.e., software and PCs fail regulary for a number of reasons that have nothing to do with Y2k. Those seem to be in a quite reasonable shape.