I'd check your proxy settings. You want it turned off (un-checked) here's how. If it is your proxy settings I'd suggest running a scan with malwarebytes (its free) when your done. Its very typical for a virus to change your proxy settings.http://www.ehow.com/how_5036562_disable-proxy-setting-internet-explorer.html
If your still not connecting I would ping a website. I always just ping google.com
This will confirm if your getting an outgoing and incoming signal. This will help decide if you have connection issues or software issues.