Vista security 2012

One of the users on my computer that has admin rights is infected with this vista security 2012  virus thing it continues to generate pop up and will not allow me to run my Symantec AntiVirus nor access the web. I have 2 other users set up on my computer which work fineand when I run the Symantec is says everything is fine. Was wondering if it is possible to run the Symantec and have it scan the infected user from one of the users that still works. Also if it is possible to disable admin rights from the infected user so it does not spread.  Also if someone might know how to remove the virus. I have tryed from safe mode as well with no luck.  Any help woutd be appreciated. As you may already be able to tell I don't know much about computers. Operating system is Vista Home Premium if that makes any differance.