The viruses get more privileges and access to system files when you are logged in as admin user. So, it is a good idea to create a limited user account for your pc and use it to access internet and for other works where admin powers are not required. Login as admin user only when it is absolutely necessary. As a further measure, you may disconnect internet when you are logged in as admin user.
Another important step is to disable auto run for CDs and pen drives (All removable media), so that the files are not opened automatically until you scan them with antivirus software.
Happy surfing !!!