Free (released under the GNU General Public License) disk defragment and optimize utility for Windows 2000/2003/XP/Vista/X64. Completely automatic and very easy to use, fast, low overhead, with two optimization strategies, and can handle floppies and USB disks/sticks. Included are a Windows version, a commandline version (for scheduling by the task scheduler or for use from administrator scripts), a screensaver version, a DLL library (for use from programming languages), and versions for Windows X64.

http://www.kessels.com/JkDefrag/

Changes:
- Fixed a bug in the Windows version that for some users caused the display of
the diskmap to get stuck.
- Fixed a bug in the forced-fill optimization that caused the program to skip
fragments that were left by filling a gap with a part of the fragment.
- If the volumename of a disk cannot be determined then the program will now
fallback to using the mountpoint of a volume to open a handle.
- If the user specifies a short input mask without a wildcard, for example "C:"
or "C:\", then the input mask is rewritten as "C:\*".
- Include the f*ckin' changelog da*nit. Make a habit.
- Fixed a bug where the special "DisableDefaults" spacehogs mask only disabled
the masks, but not the "Files bigger than 50 megabytes"" and "Files not
accessed in the last month" criteria.
- Bundled some language-specific SpaceHogs masks into
"?:\\*\\Installshield Installation Information\\*".
- Moved the "Volume ID" message for FAT disks from debug level zero to 6.

add-on:
strongly recommend to equip it with JkDefragGUI for better intuitive GUI; just download JkDefragGUI, run it to auto download JkDefrag 3.33 and u r ready to defrag

mine still in 3.32 version and my GUI dint prompt me to update.last time it will auto prompt me to update but this time not.could find any manual update button on it,do you have any idea how to fix my problem?

click on the "?" and click on "check for updates"

thanks man.didn't notice this ? previously.thought it wasn't a menu

click on "options" tab and select "on startup" then check on "check for updates on startup", it will check the latest version automatically everytime u run it

thanks and just did that and it is work!the extra cleaner feature also very useful and convenient as well.

JkDefragGUI 1.01 - 31 january 2008 @ http://www.emro.nl/freeware/JkDefragGUI101.zip

- Added automatic update of the scheduled job with newest jkdefrag when downloaded
- Added automatic update of the installed version with newest jkdefrag when downloaded
- Added croatian translation
- Added indonesian translation
- Added option to add a delay when doing a schedule at logon
- Added option to show logfile after defragmentation (GUI only)
- Added empty Prefetch folder to Internal Cleaner
- Added pagedefrag to the U3 version of JkDefragGUI
- Added JkDefrag history to menu
- Fixed helpfile not displayed on network drive
- Fixed bug JkDefrag version not updated when updated through automatic update at startup
- Fixed bug "Show System" selected on startup when disabled
- Fixed bug spacehogs disabled when selected and enabled when not selected
- Fixed bug scheduled job logfile not saved when using folder with spaces
- Fixed bug calendar not displayed correctly on Vista OS
- Improved U3 version no need re-download JkDefrag on every usage
- Removed screensaver copied to system32 during update when not installed
- Removed some external links in help menu from BartPE Mode

JkDefrag v3.34 (February 1, 2008)
Changes:
- Re-fixed the "DisableDefaults" bug.
- Partial undo of the change that uses the mountpoint of a volume. It was causing
problems during the automatic scanning for disks to be defragmented.
- Pushed the "Zone calculation" messages down to debug level 4.
- Fixed the VisualC example project.