I'm getting intermittent stop message KERNEL_STACK_INPAGE_ERROR with parameter 0xC000009D, or STATUS_DEVICE_NOT_CONNECTED, on a Compaq Proliant 800 server running NT4 SP6. This system has an imbedded Wide Ultra SCSI controller and one 9.1 gb drive and one 18.2 gb drive. Sometimes the system won't boot (doesn't see controller, drives). Usually on the second reboot it'll come up and will run ok for some time. Eventually performance degrades and there are many Disk errors in the system log. I've run diagnostics on the hard drive and so far I've not found any errors. Is it possible that this is an NT problem or is it a hardware problem? What's the best approach to fixing this? Thanks to all who consider this.