It occurred after I punched it once on the case where are no components located because I'm angry.I don't really know how can I fix it and it only happens when I play video games.
If you punch ANYTHING related to a computer, or any kind of electronics really, this is what you can expect.
How do you fix it? Well, you can try what Zerk2012 has suggested, and maybe you'll get lucky, but I'm pretty doubtful of that. There really ISN'T anyplace on a monitor, or anything else that is an electronic device or component, where you can "punch" it and not expect permanent damage. Next time, punch the sidewalk or a tree. I promise, you will immediately stop being angry because instead of breaking something else you'll likely break your hand. On second thought, don't do that, but seriously do not punch your devices. They are expensive to replace as I'm sure you are aware and to be honest modern monitors are fairly fragile so even simply pushing too hard on the screen "could" potentially affect it permanently.
Unfortunately I think this is going to end up being a learning experience because I am not very hopeful that if it wasn't doing it before you punched it, and now it is, that it is going to be fixable.
Definitely check to see that both ends of the display cable are firmly seated though. Maybe you knocked it loose. If not, probably not going to be much hope for a fix.