;;; PAGE 110,100
;;; TITLE 'EXAMPLE1.ASM' add two ASCII
;;; ;-----------------------------------------------
;;; ; Defining segment of program
;;; ; ---------------------------
;;; CODESG SEGMENT
;;; ASSUME SS:CODESG,DS:CODESG,CS:CODESG
ORG 100H
START: JMP MAIN ;1-Jump over data
;
; 1- Define data
; --------------
DATA1 DB 35H
DATA2 DB 32H
DATA3 DB ?
;
; 2- The rest of instructions
; ---------------------------

;;; 'proc'/'endp' aren't needed, define only 'MAIN' label
;;; MAIN PROC NEAR
MAIN:
;;; Note the following []s around data labels

MOV BL,[DATA1] ;2- Move 35h to BL
SUB BL,30H ;3- Change to binary
MOV AL,[DATA2] ;4- Move 32 to AL
SUB AL,30H ;5- Change to binary
ADD AL,BL ;6- Add BL to AL
MOV [DATA3],AL ;7- Store sum in DATA3
;
MOV AX,4C00H ;8- End of
INT 21H ;9- processing
;;; MAIN ENDP ; End of procedure
;;; CODESG ENDS ; End of segment
;;; END START ; End of program    

Perhaps resulting .COM would run under 32-bit Windows 8.

revolution,

That's funny, I've run that prog under 16-bit debug.exe in 32-bit Windows 7 HB before posting. AFAIK VDM support was dropped in 64-bit Windows since XP.