I've been having an issue the last month where when intermittently my keyboard will die or flicker for a second and kick back in. I will also notice some static in my USB headset when it occurs. I have gotten a new keyboard since it started and formatted and it still occurs.
Keyboard: Logitech G110 Motherboard: ASUS Rampage II Extreme Windows 7
I have updated to latest BIOS aswell, the only thing I can think of is a hardware issue, not looking forward to RMAing my motherboard=/
More aboutkeyboard intermittently cuts
You could try a powered usb hub, those backlight keyboards are quite hungry.