How can I reinstall the OS (Linux) of Eee PC 701?

I lost some of the programmes and functions when I use my Eee PC 701 (e.g. MSN, Smart pinyin Chinese input method). Also, I can't install new programmes like some other Chinese input methods on it. I can't find out the reason and so I decide to reinstall the OS. I am now using the English version of Linux. How can I reinstall it?
Thanks for your help! ^^
P.S. You may answer in Chinese. Thanks!!!