I use XP , how can I know which verison of WIFI , b ,g or n does the wireless lan card support in the notebook???

It should be listed in the characteristics of "the" notebook, along with the amount of RAM, the type of processor, the size of the hard disk... Sorry, but giving no info at all on your notebook, there is not much we can tell you. More than often, the letter "b", "g" or "n" is included in the very name of the wireless card. You can also check the properties of the card in the Device Manager ("Hardware" tab of My Computer's Properties) to see what modes are available (advanced).

Windows XP can use N speed.

Some notebooks do not support N Cards. You need to post your notebook model.