PageDefrag is a portable defragmenter that allows you to defragment files that you might otherwise be unable to defragment with typical defragmenting tools. Files such as registry, paging, event log and hibernation files or those that are open for exclusive access are just a few examples of what PageDefrag can defragment. It can be run as a system service and requires administrative access to run. This application requires only 232KB of disk space.
PageDefrag Screenshot:

Authors Website: technet.microsoft.com/en-us/sysinternals/bb897426.aspx
License: Freeware
Download: You can download it HERE