My Vista Premium Dell Inspiron 530S desktop did an auto update and then has never been able to restart. The message says something like can't recognize hard drive. Tried going to the CMOS Setup Utility and clicked LOAD DEFAULTS but hard drive simply spins on and on, doesn't seem to make any progress after 30 minutes, still spinning.
Seems like you are positive the auto update was responsible - Windows update I assume ? - Repair the OS.