Wifi turns off or disconnected in my Lenovo G400 Laptop

I'm using windows 8 on my Lenovo G400. It's CPU is intel Core i3 2.4Ghz, RAM 2 GB. Recently my laptop becomes disconnected from Wifi frequently. At first I thought its my wifi connection problem, but found my other laptops and mobile devices are connected to wifi and internet is working well. I checked some post from here asking solution for similar problems and according to them I changed my power option to high performance. However, while checking my network adaptor's driver i found the findings in the picture. Please let me know what to do to get rid of this problem. Thanks in advance