Ok, look at the bottom of this page:
link. You can also use Asus' Windows BIOS update program, which I believe is the one at the top of the page on that list. At least, that worked for my A7V333-RAID. I'm not saying it works on an A7N266-VM, since I've never tried it.
I gave detailed guidelines for making your favorite image look its best as a MyLogo 16-color image in my post in
this archived thread, if anyone needs help with that.
Incidentally, where did you hear that the A7N266-VM now supports MyLogo?