A useful utility for defragging page files, registry files etc is
pagedfrg, formerly from sysinternals - now microsoft:
http://www.microsoft.com/technet/sysinternals/FileAndDisk/PageDefrag.mspx
It's a lightweight little program, that runs stand alone - you don't install it. When you run it you see the current level of fragmentation and you can select to defrag next boot/every boot/don't defrag. It runs during the boot sequence to defrag.
I use it on every machine I work on, in conjunction with
contig (from the same author) which is a lightweight dos-style defrag tool:
http://www.microsoft.com/technet/sysinternals/FileAndDisk/Contig.mspx