A. After Service Pack 4 is applied the Windows NT operating system accesses the disk every 5 minutes which will interfere with disk power management features. This disk access is caused by a time stamp used by the Event Log service and was intended for NT Server only but has been enabled on Workstation.
To fix this perform the following:
- Start the registry editor (regedit.exe)
- Move to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Reliability
- From the Edit menu select New - DWORD value and enter a name of TimeStampInterval
- Double click the new value and set to 0
- Close the registry editor
- The change should take immediate effect. If you change from 0 to another value then a reboot is required.
See http://support.microsoft.com/support/kb/articles/Q194/7/49.ASP for more details but this has been fixed in Service Pack 5.