smiffy, have you tried PB support?
They don't seem to have US support or website anymore, but I chose the UK and found this page:http://support.packardbell.com/uk/memoryconfigurator/memory2.php?acquire=access
Even though it says Battery on that page, it seems to be for Memory. It wants a serial number which I don't have. The info you get from there may be useful in figuring out what RAM will work in the system.
If UK isn't useful, you can start at www.packardbell.com and choose a country.
Here's the main page for your computer, not much info there and the articles seem generic, but ...http://support.packardbell.com/uk/item/index.php?pn=PB82100501&g=1400