Keyboard sometimes does not work

I hope someone can help with this annoying problem.

Sometimes when I boot up, my keyboard is inoperative. I have reinstalled the plug and checked all connections. Now when my keyboard does not work I simply reboot and everything is OK - no need to check the connection.

Still this is a nuisance when the keyboard becomes inoperative and I wonder if there is something else I can do to try to eliminate this irritant.

 

I would try another keyboard and see if it happens with that one as well, then at least you can narrow it down to either a software problem or maybe your motherboard....

 

Thanks marathon851, but I already tried this keyboard with another CPU and there were no similar problems. Even though the connecting port on both CPU's seems identical, I wonder if there is a minute difference in my current CPU (probably larger) so that the connection between my keyboard and the CPU is "lost" on initial bootup; hence the inoperative keyboard. But there is no problem with my mouse connection.