回复：1st of all, Y R U still using

Thank you all for your replies. Since I can use internet at work, I don't use it that much at home. So there is no need to get a high-speed internet at home, and just try to save a little bit, since I don't earn that much. I have to be frank that I don't know how a modem works, and I don't know who to ask. Finally, I have checked my phone line and plug in, and I am positive, that both of them works well.
Do you think that there could be another possibility, like the modem just went bad, and is there any way I can find it out?
Thank you guys again.