Buy a new one with grooves which will help fixation. Some nice producers will give bouble-sided tape as a gift with the film.
There are two ways: one is to replace it with a new one, the other is to fix it with tape.
You'd better go to a computer city to buy one that matches your keyboard. I'm also using the same type of film as yours, that absorptive type.
Wash the film with liquid detergent and then put it on clean glass or desktop until it gets dry. And it will become adsorptive again when you recoat the keyboard with it!
