Then you should buy a GA-MA785G-UD3H or similar board, bilbat.
As has been mentioned in other threads, that board will drop a USB Keyboard at random for no apparent reason. It'll drop at start-up, in the BIOS, in the OS, in games, and in the middle of nothing while idle. Meanwhile, the F5B beta BIOS "fix" doesn't actually solve the problem. The problem will rear it's ugly head on different boards as well. With three AMD-based GB boards at my disposal, I've experienced the problem occurring on two of them - MA785G-UD3H and MA790X-UD4P. I haven't used the 3rd system (MA78GM-US2H) enough myself to have encountered the issue on that machine, and it's primary user hasn't reported such an occurrence to me, yet.
The problem with this issue is it's totally random. It just happens "sometimes," leaving the user frustrated and without recourse because it cannot be replicated through any specific action, meaning an RMA will be inconclusive and you'll just waste your money shipping it to and fro.