[SOLVED] Problem accessing menus, logins on websites

Hi,I've just bought an Acer Aspire 5750 with Windows 7 Home Premium 64 bit and IE9, and preloaded with McAfee Security Centre. When I visit some of my usual websites, in some cases I cannot get the login key or box to respond, or get dropdown menus to work. I've done 2 things with the laptop so far. Firstly I've downloaded and installed Norton Internet Security 2012. In doing this, not all of the McAfee seemed to uninstall, as l kept getting warnings of conflicting products (McAfee Security Centre), but it's not listed in control panel programmes, and trying to uninstall it through Norton Autofix just gave a blank screen. Also, in IE9 manage add-ons are:McAfee Inc:Site Advisor Toolbar (Disabled). Scriptproxy (Enabled). McAfee Site Advisor BHO (Disabled). Disabling scriptproxy doesn't affect the problem. The second thing I've done is download Java 6 update 30. I don't know if one of the things I've done is causing the problem, or if it was already there before I did anything. Any help would be much appreciated. Thanks Sarah.