http://support.microsoft.com/default.aspx?scid=kb;en-us;307881&Product=winxp
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Before you start to convert a FAT volume or a FAT32 volume to NTFS, consider
the following limitations and requirements:
UDF and CDFS are only used with optical media and cannot be converted to NTFS.
FAT12 is the only format used on floppy diskettes.
Some earlier programs that were not written for Microsoft Windows NT 4.0 or
for Microsoft Windows 2000 may exhibit slow performance after you convert the
FAT32 file system to NTFS. This issue does not occur on a clean partition of
NTFS.
You can use the convert command (Convert.exe) to convert an existing FAT
volume or FAT32 volume to NTFS. Because this conversion retains all your
files (unlike a format operation), use Convert.exe when you want to keep
existing files on your volumes intact.
The conversion to NTFS is a one-way process. After you convert a drive or a
partition to NTFS, you cannot convert it back to FAT or to FAT32. To restore
the volume to the previous file system, you must reformat it as FAT or as
FAT32. This action erases all existing data including your programs and
personal files. In this case, you must either restore your data from a
backup, or reinstall your operating system and programs.
Convert.exe requires that you have some free space on the drive or on the
partition to convert it. If Convert.exe determines that there is not
sufficient free space on the volume, it does not convert the volume.
If you run other Microsoft Windows operating systems on your computer in
addition to Windows XP, note the following issues:
Only Windows 2000 and Windows XP have full access to files on an NTFS volume.
Windows NT 4.0 Service Pack 4 (SP4) or later can access files on an NTFS
volume. However, there are some limitations with files that are stored by
using features from the latest version of NTFS.
Microsoft Windows Millennium Edition (Me), Microsoft Windows 98 Second
Edition and earlier, and MS-DOS cannot access files on an NTFS volume