It sounds like you may be on a laptop? If so I would recommend checking your power settings in the control panel as this may be affecting the clock speed. I'm sorry that we sent you through this route to try to get the family protection installed. You can directly install the family protection by visiting verizon.com/familyprotection.
Sounds like a multi-solution problem to say the least.
If VISS was working at one point, I would visit McAfee's website and search for the McAfee Removal Tool. It should clean out any stray traces of VISS and hopefully allow the software to re-install. What I would also do is visit http://update.microsoft.com/ and ensure you have the latest updates for your machine, ESPECIALLY service packs. If you're not running Service Pack 3, go grab it.
Otherwise, the software does not need to see the processor speed found in the Computer Properties. That is something that can be called from through an API in Windows. Two completely separate things as to how they work. To say the least, you could probably be missing that API and the software will still work.
But in any case, also double check for the presence of any other security software. They might be causing problems too if they have real-time monitoring enabled, but that's really all I can think of off of the top of my head.