请教各位老师：我设计的程序在未制作安装盘时运行正常。但是在运行可执行程序后出现了以下问题：程序运行后，关闭启动封面后进入不了主界面。主程序代码如下，请高手给帮助修改一下，谢谢！
set debug off
set talk off
set safe off
set dele on
set status bar off
set sysmenu to
set cent on
set date to ansi
clear all
clear
public rq,nf,yf,yf1,jd,jd1,gd,gj,sd,sj,fl,he,shen,flh,sh5,sh50,sh500
nf=str(year(date()),4)
yf=str(month(date())-1,2)
if yf=" 0"
     nf=str(val(nf)-1,4)
     yf='12'
     jd=str((val(yf))/3,1)
endif
if yf=" 1"
      jd=str((val(yf)),1)
      yf=right('0'+alltrim(yf),2)
else
      yf=right('0'+alltrim(yf),2)
      jd=str((val(yf))/3,1)
endif
set defa to d:\su
set bell on
set bell to "gushiyy3.wav",0
?chr(7)
set bell to
set sysm to default
do form qi.scx
READ events
_screen.Visible=.f.
_ Screen.Show
return
Clear Events
do form ma.scx
_screen.Visible=.f.

do form qi.scx
READ events
_screen.Visible=.f.
_ Screen.Show
return  &&到此为止了，
Clear Events &&结束了循环，还给你干啥？
do form ma.scx
_screen.Visible=.f.

但是我删除了return后，还是启动界面关闭后程序不能继续，请问为什么？