"GPT disks are supported only by Windows XP 64-Bit Edition. You cannot move GPT disks to computers running the 32-bit versions of Windows XP": http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/guid_partition_table.mspx?mfr=true
You need a NAS box to use 4TB disks with winXP-32.
Thanks for taking the time to reply noidea_77,
Is there a non raid nas solution that will fit my needs? I had a bad experience with a Thecus 5 bay nas, the Thecus hardware crapped itself and I was presented with the option of a very expensive repair or replacement option to get at my data. If I go non raid I can read the disk on anything.