Total 4GB RAM installed in the server but,
Available RAM is 2.49GB. Operating System is Windows Server 2003 R2 Standard Edition Service Pack 2.
Board: Intel S5000VSA
Serial Number: QSSA82800020
Bus Clock: 1333 megahertz
BIOS: Intel Corporation S5000.86B.10.00.0088.031420081550 03/14/2008
Memory Modules c,d 2554 Megabytes Usable Installed Memory
Slot 'ONBOARD DIMM_A1' has 2048 MB (serial number 5340E808)
Slot 'ONBOARD DIMM_A2' is Empty
Slot 'ONBOARD DIMM_A3' is Empty
Slot 'ONBOARD DIMM_A4' is Empty
Slot 'ONBOARD DIMM_B1' has 2048 MB (serial number 5340E810)
Slot 'ONBOARD DIMM_B2' is Empty
Slot 'ONBOARD DIMM_B3' is Empty
Slot 'ONBOARD DIMM_B4' is Empty
Memory Modules c,d
2554 Megabytes Usable Installed Memory
This is the limitation of IA-32 architecture and 32-bit OS - the total addressable memory is 4GB, and certain memory range below 4GB is reserved for BIOS, PCI-E device, VGA, etc. See http://www.intel.com/support/motherboards/server/sb/CS-010458.htm.
64-bit operating system can use memory above 4GB. If you have to use 32-but OS, try the following BIOS setting to get more usable memory:
Advanced => PCI Configuration => Memory Mapped I/O Start Address => 3.5GB
Note: If any device is not working properly after you choose 3.5GB, try 3.25GB, 3.0GB and 2.75GB in order until all devices are working properly.