If you’ve upgraded your BIOS in your ASUS M2A-VM motherboard, there’s still hope.
This last BIOS makes the motherboard almost unusable, making the operating system think that it only has between 64-128MB RAM, even if you have 8GB installed.
If you try to downgrade it through EZ Flash, it will do it returning no error, but the zero-MB-installed-RAM bug will remain.
To solve it you need to reflash BIOS 2302 from DOS with AWDFlash, with this exact command line:
awdflash.exe 2302.BIN /py/sn/f/cc/r
Reboot after that and your PC will detect all your RAM again.
Hope this helps someone!