We recently received a X61. After imaging, the system would present this message at boot.
SATA is set to Compatibility. We have imaged other X61s without a problem. I've ran the hard drive diagnostic and it passed. Operating system on image is XP Pro SP2. Imaging software is Symantec Ghost.
When you are ghosting do you ensure you capture the Master Boot Record when Capturing your image - Ghost by Default does not do this. You have to specify this in the options. This might solve your problem - If not please get back to me.