Laptop wireless connection not working

So my sister's laptop's wireless for some reason (according to her) decided to quite working all of a sudden. The build in wireless is able to detect networks and connect to them, but no data is actually transferring.

Trying to access a web page leads to an eventual time out, and trying to access the local network's computers also leads to failure.

Given that the built in wireless is able to at least detect networks, what might be the problem here? Anyone have any ideas on how to fix it?

EDIT: apparently I can access webpages using Netscape and Firefox, but not IE. I notice when I try to access a website with IE, it says "detecting proxy settings" at the bottom -- a source of the problem?

Jam it back in, in the dark.

It's not a problem with the modem here. My computer is hooked up to it (via a cable, not wireless) and so is another computer in the house, and both connect to the internet just fine. And like I said, for some reason I can use Firefox or Netscape to browse just fine, but I can't use IE or locate any other computers on the network.

The laptop is my sister's, actually, and I'm just taking a look at it for her.

There's nowhere I can't reach.

I have made sure all options were unchecked, then checked 'automatically detect settings'. Didn't work.

Also, it's not just an issue with IE, like I said. The laptop is set to the same workgroup as everyone else here, but I can't seem to access any of the other computers.

Double Post:
Nevermind, I figured out why it was like this and the whole thing is pretty stupid. Ugh.

She had Norton security's firewall BLOCK Internet Explorer. That's why it wouldn't work. I haven't yet figured out which option unblocks windows explorer from accessing the network, but I'l get to it eventually.

This thing is sticky, and I don't like it. I don't appreciate it.