Kindly let me know if there was any spillage on the keyboard?
If, as suggested by “grasshopper”, you have tried another KB and didn’t face any issue then the problem is with the Keyboard. However, if the other Keyboard also didn’t work, I would suggest you to try the below mentioned steps which could fix the issue:
• Remove any 3rd party peripherals and power cord from your Desktop, press and hold the power button for 20 seconds to discharge any residual current inside the desktop. This clears RAM and resets the hardware.
• Try resetting the system BIOS to factory defaults.
Kindly get back if there are any further queries.
Thanks & Regards