Note: To check if this document describes the computer in question, download and run a pre-install check with SymHelp.
User Account Control (UAC) is an integral part of the Microsoft Windows security model. It allows administrative users to log on to Windows with a "split token" - a limited user token is provided to logon, and when necessary the user is prompted to provide an administrative token to perform tasks that application developers and/or the operating system consider administrator-only tasks.
It should not be neccessary to disable UAC in order to install or adminster a Symantec product, but it may be necessary to run Symantec applications as Administrator, or start command-line applications from an elevated command prompt.
For more information on User Account Control, read the following articles from the Microsoft Knowledge Base: