Dick, how much of the memory is being set aside for the video on that system? It could be something like 48MB or 64MB, and that is subtracted from the 512MB system memory and is not available for Windows or applications.
Bumping your memory to a gigabyte, or even two if the laptop can handle it, (doubtful at that age) would be helpful. In truth, 512MB may be the maximum, but it would be worth checking.