Access Denied -- Administrator Account

When I was troubleshooting with Logitech on a new webcam that wasn't working,
we were trying to do a clean boot. I received the following message: "An
access denied error was returned while attempting to change a service. You
may need to long on using an administrator account to make the specific
change."

This is my personal computer and I am listed as system administrator in the
user accounts. Please help.