Freeware
Given below are freeware programs that you can download and use for free.
RegBak
Using this 'light-weight' and simple utility, you can create backups of Windows registry files to a location of your choice and then restore these files at a later date. You can also use the backups created by Regbak while running the 'Windows Recovery Console', making Regbak an ideal choice for all registry restore scenarios.

Version: 1.5
Size: 579 KB
Released on: Oct 19, 2014

Platforms: For Windows 2000, 32/64-bit Windows XP, 2003, Windows Vista, Windows 7, 8, 8.1

To download zip file instead of installer: regbak.zip (317 KB)

Registry Compactor
The Windows Registry grows as data is added to it, but it never shrinks when data is removed. A bloated registry with a lot of empty space can slow down the boot time as well as performance. Registry Defragmenter and Compactor will rebuild and re-index your registry to eliminate structural mistakes and corruption.

Version: 1.6.1
Size: 590 KB
Released on: Oct. 19, 2014

Platforms: Windows 2000, 32/64-bit Windows XP, 2003, Windows Vista, 7, 8, 8.1