Windows Internet Explorer isn't connecting to the internet and I can't figure out why...can you help?

I'm using Windows XP Service Pack 2 and Internet Explorer. My laptop was recently attacked by Malware...I believe some variant of Antivirus 2009. It disabled my internet use, plagued me with pop-ups, shut down Spybot S&D, etc. etc.. It also changed my background to a "warning, your comp is infected by spyware" (I can't remember the precise wording, unfortunately).

ANYWAY, using safe mode, Spybot S&D, Symantec Antivirus, and MalwareBytes Anti-Malware programs, I managed to get rid of the infection. However, now, Internet Explorer refuses to connect to the internet.

I use a laptop with a wireless connection to my home network. When I try to boot up Internet Explorer, I get a "cannot display webpage" message.

My Internet Options > Connections > LAN Settings are checked off on "Automatically detect settings", "use proxy server for your LAN", and "Bypass proxy server for local addresses".

As for what I've tried so far:

I removed my old version of Explorer (six), replaced it with 8, and then replaced that one with Seven. The Windows "Fix It" utility didn't fix the problem. LSP-Fix by cexx.org couldn't find any problems with my system (including my winsock, which is apparently fine...I reset that a couple times, just to make sure).

Windows Firefox is working fine; I set it to "detect proxy settings automatically" and it's got perfect connectivity. The only reason I need explorer is because iTunes runs through Explorer's connection to get to the store, and I want to purchase music.

Any suggestions on how to fix my Explorer connection, or what could be wrong? Or, failing that, how to re-route iTunes through Firefox, if possible.

Thank you!