Agam3mn0n :
This doesn't sound right. I own a Samsung 840 EVO along with 3 840 Pro's and I cant say that I have encountered this. Do you have any other disks, any other SSD's or HDD's attached to the motherboard? Perhaps the computer is trying to boot from a secondary or tertiary disk.. It's just a thought.
It is possible that the computer is simply returning a standard error message because you have not installed an Operating System on it. The message is usually something along the lines of 'Bad or mission Operating System. Please install one to proceed." If this is the message or its on a similar "missing Operating System" theme then it is not requesting the installation of DOS. It is simply requesting the installation of an Operating System as it is missing one presently.
I only have one SSD and no HDD. It asks me to pick one of the following
1) Intel 32bit XP/Win7 AHCI driver
2) Intel 64bit XP/Win7 AHCI driver
3) FreeDOS command prompt
If i pick 2 it asks for a formatted floppy
and if i pick 3 it says 'Welcome to FreeDOS (http://www.freedos.com.org)'
Please tell me how you installed your OS maybe its just a small misunderstanding. Please hurry I'm dying to play WoW
P.S All this is with the Motherboard disc in the optical drive running