What do you mean by your 'modem is very slow'?
If you mean that you have a modem capable of 56kbps and you only get 20kbps for instance, its the telephone line not the modem.
You can download manuals for ThinkPads from www.lenovo.com
If this is not your problem, try a new post with a more detailed description of the problem that you do have.
Terry
March 2006