I recently started up my computer and it was very slow. I opened Internet Explorer and a new toolbar was installed, the Connect Toolbar from Conduit. It had changed my internet homepage and I was not able to uninstall the toolbar. It must have installed itself when I installed a legitimate program. Norton did not detect any threats, but since I couldn't get rid of the toolbar, I downloaded malwarebytes and it found over 100 malicious files/registry entries from the toolbar, which luckily it was able to remove. Why didn't Norton detect this threat, or at least alert me that there was some unwanted program hidden in one of my downloads?