The wifi symbol on my HP Pavillion looks a bit like a lighthouse. It's at the top of the laptop, above the keyboard, and touching it turns wifi on and off.
Alternatively at the bottom right of the screen there are icons for power, sound etc. If the "lighthouse" symbol is there then right-click to turn it on/off. If it's not there then right-click the small arrow to open "show hidden icons". There you will find the lighthouse. Floating the mouse over it will show the state of wireless LAN and Bluetooth - right-click will give you the option to turn it on/off.