Windows XP: Please Help. I cannot get any connection to the internet.

Please Help. I cannot get any connection to the internet.

I cannot get any connection to the internet. It all started earlier today when I decided to look for themes for XP. I found one I thought I wanted, and downloaded it and installed it. During the install, my McAfee Firewall gave me 4 warnings of programs trying to access the Internet, and I blocked them all. The new Microsoft antispyware also gave me about four warnings of spyware trying to be installed. These include: InstaFinder_inst.exe: E:\WINDOWS\system32\InstaFinder_inst.exe and
Xhrmy.exe 1.0: E:\WINDOWS\Xhrmy.exe
and other programs that I can’t find any record of, like the comedy-planet.com application, and Ezula(or something with a similar name).
About 4 minutes after the install, all WebPages stopped loading. I never did see that theme show up, so I doubt it even installed it. It was probably all a lie. I uninstall all unfamiliar apps, and the ones that Antispyware found. I also uninstalled the "theme". I ran Norton AV and Spybot Search and Destroy. Norton AV found nothing. Spybot search and Destory found minor things like a toolbar.
Right now, I’m currently in the process of switching from DSL to Cable internet. 2 days ago I set up my cable Internet (Comcast) to work with my router. I’m still subscribing to DSL (AOL) Internet as well, because I have not canceled it. So I tried both in all ways possible, going though my Linksys router, going directly to the computer with Ethernet and usb connections. Still, I could not get any internet to work at all. All of this happend today. I have tried swapping network cards, but still, nothing worked. AOL Gives the following error for DSL: "Attempt 1) [DSL] An error occurred while we tried to connect you to AOL service. (24-04-30-008)"
For either cable or DSL, Windows says: "Limited or no connectivity" DSL and dial up are AOL, cable is Comcast.
I also tried 56k modem with AOL, and shortly after the modem dialed the number, AOL gave me the following error: "Attempt 1) [ Dial-up, 240-252-4698, Gaithersburg, MD] An error occurred while we tried to connect you to AOL service. (24-02-30-008)"
My other computer, an emachine works with cable, 56k and DSL, with or without the network. File and printer sharing also Is not working. Could it be a corrupted windows file(s)? Can anybody help me?

Any help would be appreciated

-Michael Ellis