I don't think you quite understand exactly what the pagefile is. I'd suggest doing some reading (starting with RAM, Virtual Memory, Pagefile and all that stuff and moving on from there if required) before messing around with any of these settings. I've only ever seen the pagefile being purged on reboot (set up via a registry key), the argument for this was to clear out any unencrpyted data which may have been stored there by certain applications.

Martin