Why does my laptop's internet not working periodically?

I have lenovo laptop and my internet is not working on LAN on Wi-Fi it works perfect.
so i bought it about 1 month ago and i had this problem: my internet works for 10 minute than stops.
i took it to sellers office they have changed my laptop to another one ( i hope so ) and it does the same thing. It's not my house's problem it works nowhere. Every time i take it from programmer internet is working for about an our then after reboot about 30 min than 10 and so on. Please guys help.

Added (1). EDIT: i know it is not driver's fault. Laptop is new and windows is 8.1 with latest drivers

Try this it is a quick fix