I apologize for the English. I am writing from Google translator. I have a problem, the CoolerMaster MasterSet MS120 Combo has broken. 1/3 of the keys on the keyboard do not work. 1/3 prints 3 characters per keystroke, 1/3 works fine! And the LED backlight does not turn on. What could be the reason? I have been using the keyboard for only 3 months.