Firefox 3.05 issue

[CheesyD]

I love Firefox and have never had an issue with it. With the latest upgrade whenever I open the browser I always get to windows opened... my normal Yahoo home page and a window pronouncing I have upgraded to Firefox 3.05. I close that window but whenever I start Firefox I always get my Yahoo home page in one and the Firefox pronouncement in the other. How do I stop the Firefox upgraded pronouncement from opening?

Thanks.