On-screen keyboard with function keys
Solution 1:
What's wrong with pressing the Fn key?
Solution 2:
If you press the Fn button on the right of the keyboard the function keys will be displayed. On windows 8 the button is on the right of the keyboard. The Function keys will be displayed on the number keys.
Solution 3:
Hit that Fn button on the right hand side of the keyboard and the F1-F12 keys will appear.