1. Go into your control panel and look for the "network and sharing center"
2. Then go to change adapter settings.
3. From there you will want to make sure that your LAN connection is properly connected to the internet and make sure that under the settings it is set to be able to share.
4. Then you will want to make sure that your wifi adapter is enabled, but is not connected to wifi already.
5. Then you will want to go back to the network and sharing center. from there you will click on "set up a new connection or network" then click "set up a wireless ad-hoc network"
6. Give your network a name and hit next all the way through setting it as you like with whatever security setting and passwords or phrases you want. Make sure you hit save network to allow you to reopen the network whenever you want.
Then you can just hit connect as if you are connecting to another network and it will start transmitting the wifi.