If you use the protected-mode (graphical) version of ScanDisk to perform a thorough scan (which includes a surface scan) on an IDE hard disk that is larger than 32 GB, ScanDisk may report errors on every cluster after approximately cluster number 967,393.
This problem only occurs on computers that use a Phoenix BIOS and use the Phoenix BitShift translation algorithm to report the geometry of large IDE hard disks (larger than 32 GB). Your computer is not vulnerable if the BIOS uses logical block addressing (LBA) Assist translation instead of the Phoenix BitShift translation.
NOTE: If you have upgraded from another version of Windows and selected to save your previous version of Windows during the upgrade, you will not be able to uninstall back to your previous version of Windows with this update installed. Disabling the option to uninstall Windows ensures that your system will continue to support your large IDE drive.
More information regarding this update can be found in the Microsoft Knowledge Base (KB), Article Q243450.