Bob is having trouble with Internet Explorer and switched over to Google Chrome. He also dumped Adobe Flash Player and Reader. Leo says that those are two apps that are a target for hackers. The nice thing about Chrome is that Flash is built into the browser and is always up to date. It's also sandboxed so it can't get to the rest of his data.
Bob is also seeing toolbars in his browser. Leo says that if he downloaded a program from a third party site like Download.com, Bob has likely installed a toolbar that came attached to the program without realizing it. Leo advises loading Internet Explorer in safe mode (with no extensions) to see if they appear. If they don't, then he'll know that's the culprit. Never get programs from anyone but the original creator. Or he'll be running the risk of getting malware, or in this case a "browser helper object."
Leo also advises going into the control panel under "add/remove" programs and uninstall anything he doesn't recognize. He could also search his system for Conduit. That's one of the worst. He can even search for programs by date and uninstall everything after the date he starts noticing the issues.