Can you open a command prompt and type "ipconfig". Start->Run->cmd
I'd just like to verify you're getting a proper IP with your wireless and not a disconnected state or seeing 169.
Are there any other wireless devices that can get internet access? If yes, then, this might sound silly, but have you rebooted the PC?
If everything else checks out, I'd like to bypass the browser. From the command prompt, type "ping yahoo.com". If we get a proper response (4 replies showing response time in ms) then we'll know the connection is good and the issue is with the browser getting blocked. And if that's the case it could be malware. At that stage I would then run malware bytes. (which you might need to download to a usb drive from another...