What @Oussebon said is a good solution. I was about to post that you should clean the dust/gunk, but since it is 1 month, it is most likely because of something else. *looks at my own keyboard not been cleaned for a year*
If you want to blame the motherboard, we're going to need to know what the make and model of the board is and what BIOS version you're currently working with. On top of that if you want to rule out your system/motherboard as faulty, did you take the keyboard over to a donor system to see if the exact issue is found on donor system?