Wireless Network adaptor not showing in Device manager, NOT WORKING.

Hi,

I have recently Installed Windows 8.1 in my Dell Studio 1555. After that, the wi-fi stopped working. Tried to check on Device manager, it wasn't showing there.Initially, Windows Vista was installed on the laptop, I had installed Windows 10 and then Windows 8.1. Earlier I didn't find any problem with using it on the laptop, but suddenly it happened after OS change. Checked by turning wi-fi ON and OFF, nothing happened, it just shows wireless adaptor not found.

Please help me to get rid of it.