Due to the windows system limitation, Windows XP only supports MBR disk format, the MBR disk format cannot support the hard drive capacity more than 2TB.
If you want to boot up from an over 2TB Areca RAID volume, below three conditions must be required:
1. Windows Vista x64 SP1 or Windows 7 64bit.
2. EFI BIOS for Areca RAID adapters and M/B.
3. GPT disk format.
There are some information about the GPT from the following link:
http://www.microsoft.com/whdc/device/storage/GPT_FAQ.mspxTags: BIOS, boot, drive, driver, install, RAID, Vista, Windows, Windows 7, XP