Can't Resize Paging File

I'm running Windows XP SP2 and have just installed Arcview GIS 3.3. ArcView
requires an initial page file size of 500 MB.

Each time I log on, I now get the "paging file not present/too low and a
temporary one has been created" error message

I go to change the custom paging file amounts and the new amounts show up in
the drive label at top. However, the bottom "total paging file size limits
for all drives: Currently allocated" remains at "0" no matter what I try to
do.

I am logged on as the Administrator. I read somewhere that Norton Antivirus
needs to have 'auto protect' disabled. That didn't work either.

How do I get the system to accept my changes to the paging file size?
Thanks in advance.

Andrew