A few days ago i detached the laptop's keyboard to clear some thick layer of dust around the heat sink. After reconnecting the keyboard to the laptop, a weird phenomenon happens that even when not touching any keys, the F6 key is constantly pressed . I have checked with a keyboard test program and finds it ranges from a short (but frequent) press (about 90ms) to a long press (up to 6000ms) and this F6-typing never stops. In particular if i type in "sd" or "ds" in normal speed, it kind of "incudes" a F6 key in.

I then looked carefully at the keyboard and found nothing wrong, at least physically, even with the F6 key. They pop up normally after pressing down. The keyboard cable also does not look damaged and other keys are absolutely normal. Some guy told me the F6 key may have been shorted..... but i'm not sure.

Well this problem quite annoys me, like when i am logging in Gmail, the text cursor just doesn't stay in password field and my password ended up showing in the location bar in firefox.

Therefore i want to know if there is anything else i can check or repair, before really considering replacing it with a new one

Thanks in advance!