When Bing just started out it used viruses and trojans to spread. You sometimes had to find this shit manually in your system folders. Since then, I delete Bing whenever I see it even for others, it also slows the browser slightly and automatically installs updates. Bing was one of the worst viruses I had.
Internet Explorer is nice for weaker pcs though because it doesnt use up as much RAM as chrome, like 1/8 of Chrome.