The utility referred to in the prior post is called "Page Defrag" and it is available from Microsoft. It allows you to defragment both your pagefile and the registry hive. On the VMWare machine we tested, although the basic files had been optimized, the page file was a complete mess as the base system was over a year old. By defragmenting we gained enough of a performance edge to make the demo at least bearable. Note this utility does not work on Vista systems.

http://www.microsoft.com/technet/sysinternals/Utilities/PageDefrag.mspx