The Natural Philosopher wrote:

I have never net a machine that didn't have the ability to have RAM in
even Gbyte increments so Id guess 4GB is possible.

Only if his O/S can handle all those memory addresses, 64 bit windows
can but 32 bit windows can't[1]. How many addresses can his O/S handle?

Incidentally isn't the amount of RAM accessible limited to 3.125GB in
the BIOS of the 530

[1] Theoretically it can but there are lots of reports about 32 bit
Windows only "seeing" 3.5 GB. Quite often this 'lost' memory has been
reserved for on-board video but with the Inspiron having a separate
graphic card all bets are off.