1)connect lap and pc to modem(through wifi or Ethernet)both should be connected modem or router

2)goto my computer ther left side you can see network there u can find your both computer name click there done(in win7)

3)if not goto control panel>network and internet>network and sharing center> there left side u can find advance sharing center click ther nxt click on public and turn on all setting save it then restart done

4)if you want access all the drives goto my computer right click on the local disk goto share with>advance sharing>click on share this folder..you can also change permission also click apply done

Your wi-fi probably have "device search"

first turn it on and your desktop must be connected to internet because ip is needed for connection

connect your desktop to internet and find your ip and then put it on wi-fi as manual search.

You need a wireless router.