. . .It was all working good and fine but tonight when I turned on my computer , suddenly I can't see my internet working. I checked and there was no wifi network available. I thought my WIFI device gone bad but it was not because my phone was using that very same wifi.

So I checked into device manager and suddenly my laptop doesn't have any WIFI adapter listed in it. And its a laptop so its WIFI device is onboard, I can't just replace it like RAM or like wifi card on desktop computer. Now I am using my phone's internet connection to post this using USB tethering.

I searched internet and seeing suggestion that turn off computer, remove card and place it back and will work. But in laptop can't do that . So what solution could be there for my problem ?

I am running windows 8.1 and there was no problem at all in my laptop before this issue.

Yes, it could be your onboard card gone useless. But have you tried turning off your laptop and then unplug it from supply and remove its battery too. It will have similar effect of unplugging the card from a desktop pc (to certain extent). Try that and let us know if that works.

Otherwise, you can buy cheap USB wifi adaptor, generally less than size of thumb drive and you can still use WIFI on your laptop.

I had issue in my laptop like yours but in my case it was driver problem. I downloaded latest company driver and ran the setup and then on reboot my wifi card was there.