How do I get SBC/YAHOO back?

Some how I have msn as my home page. I sent a message last evening, about 7:45 p.m. with the same question. What I had done was to view a video that was with SBC/YAHOO and when finished here was MSN. I do need help on this. I understand, I think, that whatever took place it was on my end? Whatever assistance you can give me will be most welcomed. Thanks, s/Richard "Dick" Purdee; dickpurdee@sbcglobal.net