Tape the button/latch under the handset on her phone down with clear tape. My favorite to do at the jail.
Or take a screenshot of her computer desktop, then use it as the image and set it to "active desktop" so when she clicks nothing happens.
Or, if you work someplace where you have lockers, seal her locker shut with clear packing tape.
Or crazy glue the rollers on her desk chair so it doesn't roll- even if you know it won't roll, you'll still try 1,000 times a day and usually fall over.
Or set the language on her computer to a language she most likely doesn't speak. Like Swahili. Or Tagalog.
Or, a little annoying one my dad did for years at work, if she is in the habit of leaving her coffee cup out and about (especially if its a travel mug), fill it with salt, pepper and ketchup packets every time you find it unattended.