Your monitor is caused by oxidation and leakage of keys on the keypad. If there is a warranty, go and have a look after the sale. If there is no warranty, go to the maintenance department to change the key. Conditional can change yourself. Give you a way to test whether the keys on the keypad are broken. Disassemble the monitor and unplug the cable between the keyboard and the main control board. If there is no problem, it must be the keyboard. If there is a problem, your main control board is broken. If so, about 80% will be repaired. The key is broken, and it will be done for 30 yuan. If you do it yourself, you can take the key apart and scrape off the shrapnel inside and the metal touching the shrapnel below with a tool until you can see that there are no rust spots. This is the easiest way, but be careful, or you can buy a soldering iron and switch keys with solder wire yourself, and there must be a sucker. That's all.