I show a John NMI Cook in Company F of the 2nd Mississippi Infantry. Now his records list his age at enlistment as 27 and not 30 or 31 which he would have been if he was born in 1830. Anyway his service summary is listed at:

http://www.2ndmississippi.org/2nd_miss_part_1/CoF/CoF4.html

Good luck in your search...

Mike