Could you tell us what OS? I'm assuming it's windows 7 though. He might have to disable the onboard GPU in the BIOS which might be reserving 256MB of space for the IGPU.
However, on that note, since he upgraded to 64bit windows, he might as well get a matched pair of 4GB of ram (2x4GB). RAM is quite cheap and easy to install.
I wouldn't suggest just sticking another stick of 4GB of ram, it might cause stability problems.
If he doesn't use photoshop, 8GB would be perfect.
Edit: I see i was a tad slow lol.
Edit 2: By the way, it would be a waste of money to go to 64 bit windows and keep that computer at 4GB. The whole reason for 64bit windows is to use more than 4GB of RAM.