A. Windows XP Service Pack 1 (SP1) and Windows 2000 SP3 add support for 48-bit Logical Block Addressing (LBA), which lets you access hard disks larger than 137GB. To enable 48-bit LBA, perform the following steps:

  1. Start a registry editor (e.g., regedit.exe).
  2. Navigate to the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\atapi\Parameters registry subkey.
  3. From the Edit menu, select New, DWORD Value.
  4. Enter the name EnableBigLba, then press Enter.
  5. Double-click the new value, set it to 1, then click OK.
  6. Close the registry editor.
  7. Restart the machine for the change to take effect.

Be aware that if you multiboot your system with OSs that don't support 48-bit LBA, editing this registry setting might cause data corruption. If you still can't access hard disk space beyond the 137GB limit after you restart your system, your system BIOS might not be 48-bit LBA compatible, in which case you need to talk to your computer manufacturer.