UltraDefrag is a powerful disk defragmentation tool for Windows. It is the first open source defragmenter with full support of system locked files defragmentation. Actually all files including registry hives and paging file can be processed by UltraDefrag during the Windows boot process.
Also one of the primary goals of the UltraDefrag design is doing the job as fast as possible.
UltraDefrag is fully compatible with Windows NT 4.0, Windows 2000, Windows XP, Windows Server 2003, Windows Vista, Windows Server 2008, Windows 7 and all of the 64-bit editions of Windows.