[H] P9X79 WS POST issues

[Winterlight]

I have a ASUS P9X79 WS motherboard. BIOS = 4901 dated in AI Suite 
II  05/07/2018. I can't get into it because at POST it displays <No 
Keyboard Found> I have tried three different keyboards in three 
different USB ports without result. Anybody ever see this behavior 
before .. any solutions. Thanks