Attached Link: http://www.sysinternals.com/ntw2k/freeware/pagedefrag.shtml

Defragmentation doesn't work on certain important system files. Pagedefrag from Sysinternals [link] is a free utility that works at boot time, before Windows gets a lock on those files, so it's a very useful addition to normal defragmentation. The best way to avoid fragmentation of your swap file is to create a new partition solely for it. That's what I did, and 'insufficient disk space' is now a thing of the past. Pagedefrag should be a good second best, though. Set it to run at every boot.