This thread covers the page file quite well with additional links as well:
http://groups.google.com/group/micro...2384fcb609d95?
What you are seeing could well be the reserved space for a dump file.
In case of a crash XP allows the necessary space to "dump" the memory.
If you wish to turn off this allowance go to:
Right click My Computer then click Properties then Advanced then Startup and Recovery | Settings
Write debugging information: set to None. Also unclick Write an event to the system log
Also delete all your dump files
.dmp
System Restore is also another possible source of used disk space. You can set the size allowance there via Properties | System Restore