Thanks for your reply Frank.
I would just like to point out that my motherboard is the D945GTP. The link below takes you to the spec.
It says in 1.4 System Memory, under the Intergrators note at the bottom of page 16, that it is possible to install four 2048 MB (2 GB) modules for a total of 8 GB of system memory,however, only 4 GB of address space is available.
Surely this would mean that I would be able to see all 8GB in the BIOS. I could be wrong as I'm not to clued up on this sort of thing.