Here is an example based on the API function GetPhysicallyInstalledSystemMemory :
include GetMemory.inc
.data
fc1 db 'Compute name = %s'
db 13,10,0
fc2 db 'The computer %s '
db 'has %u Gb of memory.',0
nSize dd 32
.data?
CompName db 32 dup(?)
Memory dq ?
.code
start:
invoke GetComputerName,\
ADDR CompName,ADDR nSize
invoke printf,ADDR fc1,\
ADDR CompName
invoke GetPhysicallyInstalledSystemMemory,\
ADDR Memory
mov eax,DWORD PTR Memory
mov edx,DWORD PTR Memory+4
mov ecx,1024*1024
div ecx
invoke printf,ADDR fc2,ADDR CompName,eax
invoke ExitProcess,0
END start