Why, when I try to take a picture of the computer screen, little black bars show up in front of it?

Question

Hmm?

Answer 1

computer screens refresh constantly, most people can't see it because how the human eyes work, but when you take a picture of it, the camera takes a picture of the moment where its refreshing so there is nothing on the screen, thats what the black bar is

Answer 2

I'm not sure why black bars show up.  Have you tried a print screen?  Press Ctrl+Print Screen, then copy it into Paint.  

Answer 3

Shutter 1/60 speed means the camera's shutter is open for 1/60th of a second. It still films at twenty four frames a second. A computer monitor set at 60hz sweeps it's cathode ray across the screen 60 times a second.

These two settings are unrelated. You can set the refresh rate till you die and it won't mean jack.

A refresh rate of 24hz will (in theory, didn't test it) just make a solid black line instead of a moving one on the monitor

A shutter speed of 1/60 will help because it will allow the film to be exposed to all the lightcoming from the monitor. For maximum exposure I suggest the highest refresh rate on the monitor.