Hi, I like to share with you my method. I had a 400gb sata drive and xp wont see the data after install until you add it to Disk Management as a Dynamic Disk because it somehow it became a dynamic disk in the past. I not sure why. For it to be seen as a Basic Disk like all the rest of your drives you have to convert it to Basic but this means you lose all your data so say Microsoft. I didn't want to lose 400gb of data. Haha. So here's a hack to convert it to a Basic Disk without losing any data. It also means i can access the drive in dos properly too. Welcome... First download this great disk editor - No need to install. http://mh-nexus.de/hxd/ - Will also open disk images. By default it reads your disks Read Only so goto Extras - Options and untick 'Read Only by Default. Next goto Extras and select Open Disk and select the right Physical Disk of the drive you want to become Basic Disk. Once opened you see the first sector on display like so. It should read 42 at sector 0 location 1C2. Change it to 07(ntfs) and then click the save icon at the top to save back to the drive. Now reboot and run chkdsk drive: /f after. Thats it, it's now a Basic Disk. Basic Disk Storage Basic storage uses normal partition tables supported by MS-DOS, Microsoft Windows 95, Microsoft Windows 98, Microsoft Windows Millennium Edition (Me), Microsoft Windows NT, Microsoft Windows 2000, Windows Server 2003 and Windows XP. A disk initialized for basic storage is called a basic disk. A basic disk contains basic volumes, such as primary partitions, extended partitions, and logical drives. Additionally, basic volumes include multidisk volumes that are created by using Windows NT 4.0 or earlier, such as volume sets, stripe sets, mirror sets, and stripe sets with parity. Windows XP does not support these multidisk basic volumes. Any volume sets, stripe sets, mirror sets, or stripe sets with parity must be backed up and deleted or converted to dynamic disks before you install Windows XP Professional. Dynamic Disk Storage Dynamic storage is supported in Windows XP Professional, Windows 2000 and Windows Server 2003. A disk initialized for dynamic storage is called a dynamic disk. A dynamic disk contains dynamic volumes, such as simple volumes, spanned volumes, striped volumes, mirrored volumes, and RAID-5 volumes. With dynamic storage, you can perform disk and volume management without the need to restart Windows. You cannot create mirrored volumes or RAID-5 volumes on Windows XP Home Edition, Windows XP Professional, or Windows XP 64-Bit Edition-based computers. However, you can use a Windows XP Professional-based computer to create a mirrored or RAID-5 volume on remote computers that are running Windows 2000 Server, Windows 2000 Advanced Server, or Windows 2000 Datacenter Server, or the Standard, Enterprise and Data Center versions of Windows Server 2003.Storage types are separate from the file system type. A basic or dynamic disk can contain any combination of FAT16, FAT32, or NTFS partitions or volumes. A disk system can contain any combination of storage types. However, all volumes on the same disk must use the same storage type.