I'm having the same problem as lisa_katherin...
I just reinstalled Windows XP (not what I wanted to do) and my Internet Explorer address bar is not working. I type in an address and hit enter, an alert message pops up saying the following:
"The requested lookup key was not found in any active activation context."
This also happened when I tried to go to "Online Support" from the Help menu or when I try to access my favorites. Luckily, I set Google as my home page and I can access different pages through the search, but that's a huge pain.
I have searched and found possible answers here:
"Requested lookup key" IE7 Problem - MSDN Forums
Basically, try uninstalling and reinstalling IE7 and then reboot. If that doesn't work, it appears other users had to reformat their computer... @_@ Man, I sure hope I don't have to do that...I just spent all day installing programs on this stupid laptop. I'll let you know how that turns out for me...