System takes a long time to boot

Just done a clean install of Vista Ultimate. Everything went fine at first,
no problems. But then it started taking a long time to boot the system. The
green scroll bar appears and moves but there's no disk access for nearly a
minute, then it continues to boot normally. Checking the event log, I have
this error during the boot process:


Event filter with query "SELECT * FROM __InstanceModificationEvent WITHIN 60
WHERE TargetInstance ISA "Win32_Processor" AND TargetInstance.LoadPercentage
> 99" could not be reactivated in namespace "//./root/CIMV2" because of
error 0x80041003. Events cannot be delivered through this filter until the
problem is corrected.


Any idea what's causing this?