Help with Wait and Regestry entries -

This is my first prog pretty simple but it is giving me a head-ache
The prog will set a dun connection
ping to establish a VPN connection
check for a file
run a .exe
delete a file
write a registry entry.
I need help making the prog stop until the .exe it calls has finished running
and closes. I also need help with the regestry.
Here is the code THANKS!!!
Private Declare Function InternetAutodial Lib "wininet.dll" _
(ByVal dwFlags As Long, ByVal dwReserved As Long) As Long

Private Const INTERNET_AUTODIAL_FORCE_UNATTENDED = 2

Private Declare Function InternetAutodialHangup Lib "wininet.dll" _
(ByVal dwReserved As Long) As Long
Private Declare Sub Sleep Lib "kernel32" (ByVal dwMilliseconds As Long)
Dim retry As Integer
Private Sub Form_Load()

retry = 1
retry1 = 1
'To automatically dial
Do
If InternetAutodial(INTERNET_AUTODIAL_FORCE_UNATTENDED, 0) Then
Sleep 5000 ' This is suspend for 5 secs 'This is to make a VPN
Shell ("ping.exe 192.19.201.444") 'connection
Sleep 10000 ' This is suspend for 10 secs
Shell ("ping.exe 192.19.201.444")
retry = retry + 5
Else
retry = retry + 1
MsgBox "Retry!"
End If
Loop Until retry >= 6

Do
If Len(Dir("C:\flag.txt")) > 0 Then 'check for flag file
retry1 = retry1 + 5 'If true out of loop
Else
Shell "c:\poll.exe" '!HELP! I need the program to stop here and
retry1 = retry1 + 1 'wait until poll.exe completes !HELP!
End If
Loop Until retry1 >= 6

Kill ("C:\flag.txt")


' !HELP! Here I need to write a registry entry !HELP!

'To disconnect

If InternetAutodialHangup(0) Then
MsgBox "Thank You!"
End If
Unload Me
End Sub