When my computer is on, it runs two instances of iexplore.exe. One uses less than 10 mb of ram (usually around 9) and the other uses over 80 mb, sometimes reaching 100 mb. This is when I'm not even using Internet Explorer. When I do open IE, it opens another iexpore.exe, but that's expected. I'm not worried about that one -- it's the first two that I mentioned that I'm worried about. I also can't End Task them either. I've tried, but they instantly come right back.
I've read some stuff online from other people who had similar experiences. Some say it's trojan, others say it's nothing to worry about. I don't know if they're bad, but it bothers me that one of them uses up so much memory.
I'm using Windows XP Pro with SP2, and I have IE7, if that matters (though I hardly use it).