Make and model for your keyboard? You might want to take the keyboard over to a donor system and see if the keyboard exhibits the same issue there(or on other system's) to rule out a faulty keyboard or that your platform lacks the necessary power off the USB port(likely a faulty PSU).
Please include/list your specs like so:
CPU:
Motherboard:
Ram:
SSD/HDD:
GPU:
PSU:
OS:
tried everything
I see only one thing changed by you...