Inspiron 15R 5537 Wireless Problem

I have recently purchased an Inspiron 15R (5537) that come with windows 8.1 Single language (Arabic). but I change the original language to English. Every driver is working except Wireless. Which sometimes working normal but often doesn't work. Please help me to solve this;

System Model number: Inspiron 15R 5537
Operating System   : Windows 8.1 64bits

Wireless Device: Intel(R) Wireless-N 7260