Vizard will not slow down your computer in general and having Vizard and Google Chrome installed on the same machine is not a problem.
If you want to reformat, first follow the instructions for unregistering Vizard:
http://www.worldviz.com/vizhelp/Unregistering.htm
and send the unregistration number and Vizard serial number to
support@worldviz.com so we can reset the license.