I have an SGI Itanium Based Altix 450 computer. When attaching a mouse and keyboard, the mouse works - the keyboard does not respond when typing/logging in. I've tried other known good keyboards. Same response. I've checked connections. The connections are good. There are 4 ports on the Altix. All 4 ports yield the same response. Usually, a computer that won't respond to an inserted keyboard has a motherboard problem. Is there any other known reason why this computer responds to a mouse, yet doesn't respond to a keyboard?