Operating System: Windows XP Home Edition 32-Bit (Version 2002) Service Pack 2
CPU: Intel Pentium Duel CPU (so I presume it means Duel Core) E2140 - 1.6Ghz
RAM: 2GB DDR2 (I think it's DDR2)
Graphics Card: Intel 82945G Express Chipset Family (Onboard I reckon) 128 MB
Screen Resolution: 1440 by 900 Desktop LCD
Result: "Fatal Error!" "Failed to Initialise Object Heap"
I'm not voting yet, 'cause this computer isn't the one I use most (in fact, I barely use this comp).
As for what graphic quality you should implement, I reckon that, if it's possible, you should offer an option to configure the level of graphical quality so the player can optimise their experience for both speed and have it looking nice.
I'm also getting that error and I use the same graphics chipset as you. I assume the problem is related to the fact that our built in GPUs are unnoticeable?