My new interesting internet connection problem
 

So recently I signed up with comcast. Since the day I signed up I couldn't connect to iTunes. This was milly annoying, but I decided not to care. I've since realized that I can't connect to GoogleEarth, Yahoo Messenger, MSN Messenger, or Auto update. To make things a little more interesting, I normally browse with Firefox, but when I open up IE it tried to go to a website, and then finally tells me it can not open a search page.
I don't understand why I can connect and browse with Trillian, Googletalk and Firefox but not with IE, Yahoo Messenger etc...

It's not so much that I want to use Yahoo Messenger, I just want to know why I can't.

I had a few problems with Comcast as well after it was installed, but nothing like what you're describing. I remedied mine by turning off the modem, router, and any computer it was linked to, and restarting in a similar order.
Maybe reinstalling those programs would help.

Just a guess but it could be a dns issue. I have the same problem with verizon. Try Treewalk dns http://treewalkdns.com/ This program was recommended at teh dsl reports forums. I have found that it does help.
You should also check to see if maybe your hosts file is somehow blocking those sites as well.

Sorry to hear you got comcast. i have had it for years but only because i have no other option where i live. its the worst ips out there and its only getting worse. when you got it installed did they install some crappy software on your computer? when i first got it installed they installed a bunch of crap that noone needed and it caused all sorts of problems ended up needing to format the hard drive to get rid of all the crap they hid everywhere. other then that just mabe a bad dns server. i get alot of dns problems as well but they normaly only happen about one day a month.

Any chance that comcast installed a firewall of some sort on your computer? Pretty much every weird internet access problem I've ever seen has been related to firewalls acting up.

I've had problems with this when I've somehow added a proxy address in IE. Some programs (I think MSN Messenger for example) use whatever connection settings are listed in IE. Therefore it could affect the other programs.
To check the proxy, go to Tools > Internet Options. Click to the Connections tab and then select the LAN settings button near the bottom. On my computer all the checkboxes are unticked and a few of the boxes are greyed out. I'm not necessarily saying that it should all be empty, but its worth noting whatevers selected at the moment, trying it, and then if it still doesnt work put it back to how it was.

Hope that helps,
Bahh