I am using Masm32 and am pretty new to Assembly, but I am having trouble trying to assemble and link this code:

Code:
;Io1.asm:  Displays character that is entered on the keyboard

    .model small
    .stack 100h

    .code
start:
    mov ah,1h       ;character input sub-program
    int 21h         ;call ms-dos to read character
                    ;al now contains character from keyboard
    mov dl,al       ;read character from register al
    mov ah,2h       ;character output sub-program
    int 21h         ;call ms-dos to display character

    mov ax,4c00h    ;return to ms-dos
    int 21h
    end start
I keep getting an error message that says "LINK : error lnk2001: unresolved external symbol _start"

Please help...this is driving me crazy!!!!