can I de-activate a HDD with winxp-ntfs on it, WITHOUT destroying the data 'thereon'??

Ummm not sure overall what you mean but if you want to change the current structure of the disk then you probably need some help from third party programs


PartitionMagic
http://www.powerquest.com/partitionmagic/
PartitionMagic® allows you to create, resize, merge and convert partitions on your hard drive without destroying data. Award-winning PartitionMagic is the world's leading hard-drive partitioning software for PC enthusiasts.

Partition Manager
http://www.partition-manager.com/n_pm_main.htm

Partition Manager from Paragon provides easy and safe partitioning functions to even non-professional users.

With Partition Manager you can reclaim wasted disk space, organize your data, add new operating systems, speed up file system performance.

In the past, partition modification was risky and time-consuming task. Users had to backup all files, create new partitions, format them, may be reinstall operating system, and restore data. With Partition Manager you just select what partition modification should be done. All will be done automatically without  data loss.

System Commander
http://www.v-com.com/product/sc7_ind.html

System Commander 7 provides the ultimate OS management and full partitioning in one integrated package!

 Supports every PC-compatible OS!
 Automatic preparation for adding OSes
 New - user selectable graphics
 New - installs from any Windows, including Windows XP NTFS.
 Free! Partition Commander 6 - Safe resize, create, move & copy for Windows 95/98/Me/NT/2000/XP, Linux and DOS partitions.
 Undo partitioning with exclusive BackStep technology.

Partition Commander
http://www.v-com.com/product/pc8_ind.html

Partition Commander lets you reclaim hard disk space, organize your files, add new operating systems (OSes), and in many cases speed up hard drive access speeds. Best of all, you don't have to be an expert. Partition Commander automates the process - guiding you through step-by-step. Where you have a choice, helpful suggestions are made available - the rest is handled automatically!

BootIT Next Generation
http://www.bootitng.com/bootitng.html

BootIt NG is a partition and multi boot manager with a powerful and simple to use set of tools for partitioning, imaging, and multi-booting your computer.  It combines the features of several standalone products costing hundreds of dollars more.

Here's a list of some of the features you'll find in BootIt NG:

Windows XP/2003 Compatible!
IEEE1394/USB 2.0 high speed support for imaging/partitioning.
support for large hard drives (2 TB) and partitions (1-2 TB).
non-destructive resizing and conversion for FAT/FAT32.
non-destructive resizing for NTFS.
creation and (secure) deletion of partitions/volumes.
undelete partitions/volumes.
FAT/FAT32 formatting
copying and moving of partitions/volumes.
support for Linux Ext2/Ext3 and ReiserFS file systems.
Imaging (including directly to CD-R/RW or DVD+R+RW-R-RW)
booting any partition on any hard drive  
booting from the CD ROM drive
booting multiple operating systems from a single partition.
create over 200 primary partitions (if desired).
user id and password protection.
free upgrades (1.00-1.99) (registration-key versions only)  
and lots more....

zBoot Manager
http://www.zbmsoft.com/

zBoot Manager is an effective boot manager and partition manager, which allows you to easily install and use multiple operating systems on a single hard drive.


Acronis PartitionExpert
http://www.acronis.com/products/partitionexpert/

Resize, copy, and move partitions without losing data*
Create and delete partitions of any type
Format partitions*
Automatically optimize hard disk space usage
Convert FAT16 <=> FAT32, Linux Ext2 <=> Ext3 partitions without losing data
Change cluster size, automatically or manually**
Browse through the detailed information about all hard disks, partitions and file systems
Hide or make visible partitions of any type
Previewing changes made in partition layout before applying them to disk
Supports large disks over 180 Gb
----------------------

Free

Ranish Partition Manager
http://www.ranish.com/part/
Partition Manager is a freeware program that partitions hard disks. It will help you to install and dualboot Linux and multiple copies of Windows. For example, it will let you to run Win ME, Win 2k, and Linux on a single box. Also, using Partition Manager you can copy, move, and resize disk partitions.

Partition Resizer
http://www.zeleps.com/
New features include:

 Int13 extensions support allows handling of disks up to 2TB (2048GB) of size.
 New Resizing/Moving engine with simpler inerface. Move and resize your partitions in one step.
 Transparent extended partition resizing (no more confusion with extended partitions).
 Command line parameters for accessing advanced options (read-only operation etc.).

Partition Resizer is a small DOS executable, which requires no installation, and can perform, all these tasks in a short while, giving you the opportunity to re-arrange your partitions safely, quickly and fuss-free.

3D Partition Manager
http://www.sofotex.com/3D-Partition-Manager-v.-2.37.10-download_L1884.html
3D Partition Manager Publisher's Description:
Partition Manager - create, delete, resize partitions. Format and resize FAT-16 and FAT-32 file systems. Advanced Boot Manager - select active partition at the boot time, boot from the second hard drive. Hide/unhide partitions. Create up to 31 primary partitions on a single hard drive



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