GhislainG and soundefx, thank you so much for your kind reply and I really appreciate it. Today I send my pc to the shop I bought it to claim warranty. When the technician plug Lan wire into the problem lan slot, its work perfectly. And he also tried to connect internet Wifi using his USB Wifi adapter. So he install the USB wifi software in my pc. After the software was install in my pc, the technician unable to find the Wifi program that he was install. He say its software problem that may caused by spyware or virus. So he advice me to format the pc. Tomorrow I will save all my media files and try to format my pc.