Hi Mark,
thanks for your interest in Vizard -- I don't know about the details of your system clock, but what we can do for sure is to unlock your version of Vizard for the remaining time.
In order to do this, please contact
sales@worldviz.com, and shortly describe what happened, and one of my colleagues will be able to unlock Vizard on your computer for a limited amount of time.
Also there is the option to purchase Vizard LITE for $79 off this webpage, which works without time limit and is good for most developments.