My Basic Program stops and screen goes blank -please help?

Question

Any help would be greatly appreciated!! Here's what is happening:

When I choose #1 Recieving at the main menu that takes me to the "scan code" screen. Ok, so I want to quit and go back to the main menu so I press the F1 key (CRT$). When I go from this screen back to the main menu a couple of time the screen goes blank and the program stops. Should I put the "go back to main menu" command somewhere else note: I have commented out choices 2 thru 4 until I solve this.

Please help-I'm stuck!

'+===========================================================================+
'|  Declaration variables                                                    |
'+===========================================================================+
 private tempkey$
 private ver$
 'DIM FMAX%
 DIM TBL$ 
 DIM F1$ 
 DIM F2$ 
 DIM F3$
 DIM F4$ 
 DIM UP$ 
 DIM DN$ 
 DIM CL$ 
 DIM CRT$
'
 DIM NO$  
 DIM YES$
 DIM CAN$
 DIM CR$
 DIM BS$ 
'+===========================================================================+
'|  Initial Settings                                                         |
'+===========================================================================+
 ver$ = "1.02"
 out &h6080,1                    ' Set to small-size font

' 
 OUT 6,0
'+===========================================================================+
'|  Main menu                                                                |
'+===========================================================================+
 FMAX%= 99
 TBL$ = "-YZ+UVWQRS"
'
 '
 F1$ = "A"
 F2$ = "B"
 F3$ = "C"
 F4$ = "D"
 UP$ = "E"
 DN$ = "F"
 CL$ = "G"
 CRT$ = "H"
'
 NO$ = "D" 
 YES$= "C"
 CAN$= CHR$(24)
 CR$ = CHR$(13)
 BS$ = CHR$(8)
' 
 OUT 6,0
main: 

     while 1
       beep 3,1,1,1
       'Display
        cls
        'screen 1,1
        'print "  Stellar  ";ver$
        screen 1,0

menu1     '  
  print "" 
          print "1.Receiving"
        ' print "2.Cycle Count"
        ' print "3.Phy. Inventory"
        ' print "4.Send"
         'print "5.Review Data"

 ON ERROR GOTO ERRRCV

       'Go to each process
       'GOSUB KBCLR
  wait 0,&h01
        tempkey$ = inkey$
        beep 1,3,1,1
        select tempkey$
            case "1":
                gosub menu
 ON ERROR GOTO MENU
           ' case "2":
            '   gosub menu
           ' case "3":
           '    gosub menu
            'case "4":
 'gosub menu   
           'case "5": 
 'gosub BARIN3
               ' power 0
 'ON ERROR GOTO ERRRCV
        end select   
    wend


menu '

'
'       ******************************************
'       *    Main                                *
'       ******************************************
 ON ERROR GOTO ERRRCV
 SCREEN 0,0
 BEEP 2
 SCODE$ = "             "
 SURYO$ = "   "
MAIN0 '
 CLS

 GOSUB FILOPN
 KEN% = LOF(1)
 IF LOF(1) >= FMAX% THEN 
  GOTO DSEND0
 ENDIF
 IF tempkey$ = "4" THEN 
  GOSUB DSEND0
 ENDIF

MAIN1 '
 MN%=0 : GOSUB DSP0

MAIN2 '
  GOSUB BARIN 
MAIN3 '

 IF W$ = F1$ THEN 
  GOTO DSEND0 
 ENDIF
 SCODE$ = BAR$
 SURYO$ = "1"
 MN%=1 : GOSUB DSP0 
 BAR$ = ""
 GOSUB KOSUIN
 GOSUB FWRT

 IF W$ = UP$ THEN
  GOSUB BARIN3
 ENDIF
 IF W$ = F1$ THEN
  GOTO MAIN3
 ENDIF
 IF LOF(1) >= FMAX% THEN
  GOTO MAIN0
 ENDIF  

 MN%=2 : GOSUB DSP0

 IF BAR$ <> "" THEN 
  GOTO MAIN3
 ENDIF 
  GOTO MAIN2 

'       ******************************************
'       *    Input Bar Code                      *
'       ******************************************
BARIN '
 'KFLG% = 0
 'SYS% = 0
 'ON ERROR GOTO ERRRCV
 'WAIT 0,&h03
 W$=INKEY$

 IF W$ = CRT$  THEN  ‘ Press the CRT$ button(F4) to go back to main      ‘ menu
  CLOSE #1
  CLOSE #2
  END
  GOSUB main:

 ENDIF

 KFLG% = 0
 GOSUB BAROPN
 GOSUB KBCLR
 SYS% = 0
 IF MN%<>0 THEN
  LOCATE 1,1
  PRINT CHR$(3);
 ENDIF


BARIN0 '
 IF EOF(2) = 0 THEN 
  GOTO BARIN1 
 ENDIF
BARIN2 ' 
 WAIT 0,&h03
 W$=INKEY$

 'ON W$ = CRT$ GOSUB main:


 IF W$ = CR$ AND KFLG% = 1 THEN
  KEN% = LOF(1)
  GOSUB FREAD
  G% = 0
  MN%=2 : GOSUB DSP0
  GOTO BARIN
 ENDIF 
 IF W$ = F1$ THEN
  RETURN
 ENDIF
 IF W$ = "" THEN 
  IF KFLG% = 1 THEN
   GOTO BARIN2
  ELSE
   GOTO BARIN0
  ENDIF
 ENDIF
BARIN3 '
 IF W$ = UP$ AND KEN% >= 1 THEN
  IF MN% <> 0 THEN
   KEN% = KEN%-1
  ENDIF
  IF KEN% > 0 THEN
   CLOSE #2 
   GOSUB FREAD
   MN%=8 : GOSUB DSP0
   KFLG% = 1
  ELSE
   KEN% = 1
  ENDIF
 ENDIF
 IF W$ = DN$ AND KEN% < LOF(1) THEN
  KEN% = KEN%+1
  GOSUB FREAD
  MN%=8 : GOSUB DSP0
 ENDIF
 IF KFLG% = 1 THEN
  GOTO BARIN2
 ENDIF
 IF MN% = 0 THEN
  IF W$ = MID$(TBL$,SYS%+1,1) THEN
   SYS% = SYS%+1
  ELSE
   SYS% = 0
  ENDIF
 ENDIF
 IF SYS% >= 10 THEN 
  CLOSE #2
  GOSUB SYSUTY
  MN% =0 : GOSUB DSP0
  GOTO BARIN
 ENDIF
 GOTO BARIN0
BARIN1 '
 INPUT #2,BAR$
 BEEP 1
 CLOSE #2
 RETURN
 '


'       ******************************************
'       *    Input item quantity                 *
'       ******************************************
KOSUIN '
 GOSUB BAROPN
 GOSUB KBCLR
 X% = 0
 SURYO$ = "1"
KOSU0 '
 LOCATE X%+13,3
 WAIT 0,&h03
 W$ = INKEY$
 IF EOF(2) = 0 THEN 
  SURYO$ = MID$("000",1,3-LEN(SURYO$))+SURYO$
  GOTO BARIN1 
 ENDIF
 IF W$ = F1$ THEN
  SURYO$ = MID$("000",1,3-LEN(SURYO$))+SURYO$
  RETURN
 ENDIF  
 IF W$ = UP$ AND LOF(1)>=1 THEN
  SURYO$ = MID$("000",1,3-LEN(SURYO$))+SURYO$
  RETURN
 ENDIF  
 IF W$ = "" THEN
  GOTO KOSU0
 ENDIF
 IF W$ = BS$ THEN
  IF X% > 0 THEN
   X% = X%-1
   SURYO$ = MID$(SURYO$,1,X%)
   IF SURYO$="" THEN 
    SURYO$="1"
   ENDIF
   LOCATE 11,3
   PRINT SURYO$;MID$("   ",1,3-LEN(SURYO$));
  ENDIF
  GOTO KOSU0
 ENDIF
 IF W$ = CAN$ THEN
  SURYO$ = "1"
  X% = 0
  LOCATE 11,3
  PRINT SURYO$;"  ";
  GOTO KOSU0
 ENDIF
 IF W$ = CR$ AND LEN(SURYO$) > 0 THEN
  BEEP 3 
  SURYO$ = MID$("000",1,3-LEN(SURYO$))+SURYO$
  LOCATE 1,3
  PRINT " ";
  RETURN
 ENDIF
 IF X% >= 3 THEN 
  GOTO KOSU0
 ENDIF
 IF ASC(W$) < ASC("0") THEN GOTO KOSU0 ENDIF
 IF ASC(W$) > ASC("9") THEN GOTO KOSU0 ENDIF
 '
 BEEP 1
 PRINT W$;