Internet Explorer hates itself!

Not quite, but it’s kind of like that. Here’s my problem: my computer at work has started to act funny. I do a lot of web design work, hence the need to check my pages in IE 6. Long story short, whenever I try to type a website into IE’s address bar and press enter or “Go”, it automatically opens up the page in Firefox (and the page stays the same in IE, it doesn’t open it). So basically I can’t preview any pages in IE, since they all open up in Firefox.

Anyone have this problem before?