Ya you are on the low end with this computer. It takes about 512 megs of ram just to run XP, and like krusty said the video card is a low end card, but the good news is you should still be able to get it to play. You'll have to turn everything down, and if you were a bit more computer savy you could tweak your computer a bit to get it to run a bit faster.
start the game and click on the "Video settings button" You may have to knock down your resolution to 800x600, but make sure your "max texture size" is down to 128, and that neither "pre-load" box is checked in the textures box. Click ok, and when the main screen pops back up again start the game in off line mode. Check and see how it runs. Its not going to be the prettiest, but it should be able to run.