This is has got to be WinXP.
First check that the memory size jives in System properties.
Use CCleaner to clear your TEMP folder.
Make sure to have 1GB free space on your hard disk.
Set page file size to 'manual' with 4096GB size. Set to 'Auto' WinXP arbitrarily assigns 1.5x memory space as page file size.
Hope this helps.