But there is a better way than sitting wondering what else might be compromising your browser, and that's to do what I did a year back... change to the Opera browser (www.opera.com)
The latest version is just as good as IE. It formats webpages the same, and has as many features - if not more. One I particularly like is the ability for mouse gestures for shortcuts. Click your right mouse key and describe an "L" on your web page, and the page closes. No need to move up and find the "Close" icon.
Or your can right-click and move the mouse straight down, and a new page opens. There are many shortcuts like this.
But the best part of using Opera is the speed. It is very fast. While I'm loath to say it is 10 times faster with all web sites for everyone, this is actually the speed improvement I've found. With ADSL and Windows XP I get an almost instant page open on 90% of all sites. In fact, up to 2 seconds is the longest time I've had to wait for many pages.
IE on the other hand is much slower, taking up to 10 seconds for the same page. I still have it installed to remind me what 90% of all net users experience!