NTREGOPT 1.1j

Similar to Windows 9x/Me, the registry files in an NT-based system
can become fragmented over time, occupying more space on your hard
disk than necessary and decreasing overall performance. You should
use the NTREGOPT utility regularly, but especially after installing
or uninstalling a program, to minimize the size of the registry files
and optimize registry access.

The program works by recreating each registry hive “from scratch”,
thus removing any slack space that may be left from previously
modified or deleted keys.

Note that the program does NOT change the contents of the registry in
any way, nor does it physically defrag the registry files on the drive
(as the PageDefrag program from SysInternals does). The optimization
done by NTREGOPT is simply compacting the registry hives to the
minimum size possible.

Download: NTREGOPT 1.1j