Chesseball good work! I notice U refered to masmv5 if U are using it I would sugguest using Masmv8 it's better. Looking at your code I challenge myself to optimize it off the top of my head.

Code:
.code
start:
        mov ax, 03h
        int 10h

        mov dx,  message
        mov ah, 09h
        int 2fh
  
        mov ah, 01h
        int 2fh
       cmp al
       je No
       jne  start

Yes:
      mov ax 03h
      int 10h

     mov dx, Uyes
     mov ah, 09h
     int 2fh
     jmp close
No:
     mov ax,03h
     int 10h
     mov dx, Uno
     mov ah,09h
     int 2fh
close:
     int 20h
remember it's off my head this would work also. U didn't need the "jmp close instruction" after the code in the 'No lablel' it's only wasted processor time and slows program down.
but I have to give to U Cheeseball keep it up and maybe U'll convert the C and C++ heathens%-<|> anyway good work