Probably, your disk is forgetting the geometry that was uploaded to it.
After the machine is powered back up, it needs to be reset.

Do you know if this machine supports APM?  I'm (slowly) working on
proper APM support.  If it's some proprietary Compaq scheme, then I
probably can't help you.

(BTW, the APM code that's been floating around *doesn't* deal with the
geometry issues.)