Help Me PLEASE :(

[trebla21]

Somebody help. This is for my special project and to be submitted on monday. It's 11:09pm (saturday) here. i have a problem with my codes. its about when you input a CAPITAL LETTER the output should be in lowercase and vice versa. and also my problem is i dont know to code the " INVALID INPUT" when the input characters have spaces and numbers. that's all. hope someone will help :( i need to pass my subject :(

Here's my code....

DIS MACRO STR
MOV AH,09H
LEA DX,STR
INT 21H
ENDM
DATA SEGMENT
MSG1 DB "INPUT A CHARACTER : $"
MSG2 DB "CONVERTED CHARACTER IS : $"
STR1 DB 20 DUP('$')
LINE DB 10,13,'$'
DATA ENDS

CODE SEGMENT
ASSUME DS:DATA,CS:CODE

START:
MOV AX,DATA
MOV DS,AX
DIS MSG1
MOV AH,0AH
LEA DX,STR1
INT 21H
DIS LINE
MOV CH,00
MOV CL,BYTE PTR[STR1+1]
LEA SI,STR1+2

L1: MOV AH,BYTE PTR[SI]
    CMP AH,'A'
    JL L4
    CMP AH,'Z'
    JG L2
    ADD BYTE PTR[SI],32
    JMP L3

 L2:CMP AH,'a'
    JL L4
    CMP AH,'z'
    JG L4
    SUB BYTE PTR[SI],32

 L3:INC SI
    LOOP L1
    DIS MSG2
    DIS STR1+2

L4:MOV AH,4CH
INT 21H
CODE ENDS
END START

;------
;OUTPUT
;------

ENTER YOUR CHARACTER : JiNeSh
CONVERTED CHARACTER IS : jInEsh

[Assembly Guy]

This is for my special project and to be submitted on monday.

So what you're asking is basically

Can you do my work for me?

[Bhavya scripted]

nobody is gonna hep you you ASK people to do your homework

[Schol-R-LEA]

The origina; post was from two months ago; it is safe to say that the 48 hour deadline has long since passed. :-p