curupted my cd
Yes. Any computer manufactured since 2002, including the Intel D945GCPE, can support a theoretical maximum of 144 petabytes (144 million gigabytes) per drive.
As the motherboard has only two expansion slots, both PCI, your options are rather limited. You would need to purchase a PCI graphics card, which probably isn't worth the money.
http://www.intel.com/support/motherboards/desktop/d945gcpe/sb/CS-027116.htm2 GB maximum total system memory
Graphics cards do not typically function in this manner. While cards can, in some instances (using SLI or CrossFire), share resources, the memory address spaces are kept separate, and the GPU workload is simply divided. This is also dependent on the game software itself. Also, neither of the two methods for connecting cards in the aforementioned scenario work on AGP or PCI buses, but only on PCI-E buses.