Why are Internet Explorer Temporary Internet Files being Created?

[fredpeterson543]

I use Firefox as my default and a little bit of Opera but never use internet explorer. But when I run ccleaner it shows almost 140 internet explorer temporary files being deleted. I run this every day and it's there every time. Is some program that I don't know about running on my machine and secretly using internet explorer? (I have avast and antispyware running). Could this be related to my using Outlook?