Avoid installing things you did not ask for, for example Google Toolbar, Google Desktop, Safari, Microsoft Bing, Microsoft Live, Chrome, McAfee virus checker, Ask toolbar or Yahoo Toolbar. Lots of programs you download, even the ones you want will automatically install programs you did not intend to ask for. Watch carefully. Usually, you can uncheck a box and avoid them. It is called negative optioning.
You do not need the Google toolbar, or any other toolbars. They use lots of resources (slows your computer down) and provide no value. In the top right corner of your Internet Explorer window is a search box (it could be Google, Bing or Live) that is part of Internet Explorer. Just type your search in there. In Windows 7, your Internet Explorer address bar doubles as a search box.