My systems freezes and I have found this event in my system event log as error and the registry is point to the Symantec Hash Provider.
Key Name: HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\Root\LEGACY_CCHP\0000
Class Name: <NO CLASS>
Last Write Time: 7/26/2011 - 7:51 AM
Value 0
Name: Service
Type: REG_SZ
Data: ccHP
Value 1
Name: Legacy
Type: REG_DWORD
Data: 0x1
Value 2
Name: ConfigFlags
Type: REG_DWORD
Data: 0
Value 3
Name: Class
Type: REG_SZ
Data: LegacyDriver
Value 4
Name: ClassGUID
Type: REG_SZ
Data: {8ECC055D-047F-11D1-A537-0000F8753ED1}
Value 5
Name: DeviceDesc
Type: REG_SZ
Data: Symantec Hash Provider
Value 6
Name: Capabilities
Type: REG_DWORD
Data: 0
Key Name: HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Enum\Root\LEGACY_CCHP\0000\Control
Class Name: <NO CLASS>