A window keeps popping up on my Macbook Pro. with this address http://seth.avazutracking.net/ Google search said it is a virus. PLEASE HELP!!
You can't really trust Google's results on this one. It's often the case that obnoxious pop-up windows are claimed to be caused by a virus by people in many public forums, when that's not actually the case. In the case of Mac users, it's almost certainly not malware of any kind... see my Mac Malware Guide.
As to what it is, there are a number of causes for this sort of thing. One is that some website you frequently have open in your browser is opening this pop-up window. In the Privacy pane of Safari's preferences (assuming you are using Safari), make sure to check the "Block pop-up windows" option is checked. That's no guarantee, though... some advertisers are still able to get pop-ups to open anyway, in my experience. If you can figure out what site it is, you can ask the creator(s) of that site to remove this particular ad and boycott the site until they do.
Alternately, if this window is opening all the time, no matter what sites you have open at the time, then it's possible you have installed some kind of junky browser extension or plug-in that is causing it to open. What do you see in the list in the Extensions pane of Safari's preferences?
It's also entirely possible that this is due to advertising code being injected into pages by your network provider. This can be the case with free wifi providers, who sometimes use such techniques to make advertising revenue. Is this only happening with one particular network?