Spontaneous reboots :(

[Cliff]

Hey all,

So my K6 has rebooted mysteriously three times since Saturday morning.
I'm running behind my P90 with masquerading so I don't suspect outside
intervention.  More to the point, the computer doesn't survive the Power
On Self Test and sits there while my Maxtor hard drive makes
really-not-so-good sounds intermittently.  I obviously suspect this is
the cause of my troubles (ie bad hard drive), but I've never seen one go
bad such that a machine reboots with no error messages in logs or
anything.  The maxtor disk diag tool finds nothing wrong yet I have to
power cycle (plain reboot won't do it) the machine for the drive to
recover and then it acts fine until the box reboots again.  I don't
suspect memory would have suddenly gone bad on me...any ideas?  Or am
I just S.O.L...

Cliff