Check to see if you can ping a website. Open up command prompt and do a ping to get some replies.
Example: ping www.google.com
Then check the explorer setting. Control Panel>Internet Options>Security Tab. Make sure those are at default setting, if they are too high they might not allow you to connect.
Check the privacy tab, make sure the cookie setting aren't too high. Medium is good.
Check the Connection tab>Lan setting button. Make sure nothing is check and no entry are added for the proxy server.
Other options: Download Firefox from another computer and transfer it to your computer. Use Firefox to connect to the Internet.
Firefox link
Firefox - Rediscover the Web
You can try and reinstalling IE 7
Get it here
Internet Explorer: Home Page