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It is best in low memory circumstances to let the system set the size of pagefile.sys. Upgrading to 2Gb will make a huge difference and the settings won't need to be changed if you let the system take over. It will automatically allocate one and a half times physical memory to pagefile to 2Gb gives you three whereas 1Gb only give you 1.5.
Defragmenting the hard disk occasionally helps a little - pagefile.sys can fragment as much, if not more, than any other file.