unable to log into email account


New Email
doing a web search and the screen flickered and then remained stable, I closed Firefox and later started it up to check my email. I had lost my home page (AT&T Yahoo) and it hade been replaced by a lot of text from AT&T. After several hours i finally restored a stripped down version of my home page but when i try to access my email (sign in ) nothing happens. After entering my user name and password it just sits there. can anyone give me some help