|Extracted from http://aumha.org/a/stop.htm|
A necessary Registry hive file couldn’t be loaded. The file may be corrupt or missing (requiring either an Emergency Repair Disk or a Windows reinstallation). The Registry files may have been corrupted because of hard disk corruption or some other hardware problem. A driver may have corrupted the Registry data while loading into memory, or the memory where the Registry is loading may have a parity error (turn off the external cache and check the physical RAM).
Much more info available on the WWW, worth spending some Google time.
Please come back & tell us if your problem is resolved.