Symantec Antivirus Win64 shows error on startup

Hello,
I am new in the computing arena but I know the importance of having an antivirus. I installed Symantec on my computer but since then I get the following error on start up. Can anyone assist me to solve this error?

This version of Symantec Antivirus Win64 requires elevated privileges in order to install. Please log in as an administrator, or contact your network administrator for help.
