dial-up question

Hi,
I used dial-up to surf on internet at home. However, since yesterday, every time when I try to connect internet, it says that " there is no dialing tone". I have checked my password and the plug-in. Everything was fine, and I have just used it the day before yesterday, and I did not do anything to it at all. I am wondering if someone could please give me some suggestions.
I really appreciate it.