Wow....It's more hidden than I thought. M$ must not want you to screw with this setting

Anyway, it's in the System Properties dialog (Win+Pause, or right click on My Computer -> Properties)
Advanced Tab. There should be 3 "boxes" there, each with their own Settings button. Click on the Settings button for Performance (First "box")
In the Performance Options, click on the Advanced Tab. The virtual Memory (swap) options are at the bottom. Click on the Change Button, then click on the option for "No Paging File"
Click several OK buttons and it will tell you to reboot. Do so and then run your defrag. Reverse the procedure to turn the swap back on (Important in Windows)
Hope that helps you out.