Ok, Window 8.1 is I guess a better version. However, after upgrading, wifi stops working on my sister's lenovo ideapad s400 touch laptop. I tried to reinstall the whole window just to find out the problem caused by the driver. The Broadcom wireless adapter works fine under window 8 but not 8.1. For some reasons, driver does not work, it shows error "limited connection". How to fix it? well, I just have to search for the driver on Lenovo website. I went to lenovo website just to find out that the driver is not available for 64 bit. It's a feature and should be pre-implemented in window 8.1. So I had to go search for the web and finally found the driver I was looking for.
here is the link: https://drive.google.com/open?id=0B2aGUKMcMA9UNzRQWTVOX0tDalE&authuser=0
