There is some thing about 2TB limitation on Microsoft Windows' file system.

1. To use the disk that over 2TB capacity, Microsoft Windows had to convert the disk to GPT.
2. For Microsoft Windows XP, only 64-bit edition supports GPT, which means all the other 32-bit version Microsoft Windows XP are not support the disk larger than 2TB.
   
3. Microsoft Windows Vista x86 (32-bit) & x64 (64-bit) & Windows 7 (32bit & 64bit) support GPT, which mean Microsoft Windows Vista & Windows 7 can handle over 2TB disk well. but the disk have to convert from MBR to GPT in Disk Management.

Reference:

• Windows and GPT FAQ (http://www.microsoft.com/whdc/device/storage/GPT_FAQ.mspx)