If you have a laptop, maybe there's a physical switch on the front or the side or a Function key with the wi-fi icon on it that needs to be pressed to turn it on. Sometimes, you might need to press the Fn key to the left of the Spacebar at the same time. Device Manager should show it under the category of Network Adapters. If it really isn't there, there's a connection problem or the device has given up.
TIP: Writing in all capitals is the Internet equivalent of shouting.