Since Windows Server 2003 SP1, user-mode access to physical memory has not been possible. You will have to develop a driver to do it (or find a third-party tool that includes one).
From Technet:
In Windows Server 2003 SP1, user-mode access to the \Device\PhysicalMemory object is not permitted. All forms of access (read, write) are refused when the \Device\PhysicalMemory object is accessed from a user-mode application. Access to the \Device\PhysicalMemory object is refused regardless of the user context (Administrators, Users, Local System, etc.) the application is running in.