При запуске посторонней программы виснет форма

Option Explicit
 
Private Sub Command1_Click()
 
Dim f1 As String
Dim f2 As String
 
ReDim Buf(1023) As Byte
Dim Done As Long
 
f1 = 'E:MP3DJ Virgendj_virgen_-_enlightened.mp3'
f2 = 'C:1.mp3'
Open f1 For Binary Access Read As #1
Open f2 For Binary Access Write As #2
Do While Done < FileLen(f1)
    If FileLen(f1) - Done < 1023 Then ReDim Buf(FileLen(f1) - Done)
    Get #1, Done + 1, Buf()
    Put #2, Done + 1, Buf
    Done = Done + UBound(Buf)
    Caption = Round(Done / FileLen(f1) * 100, 2) & '%'
Loop
Close #1
Close #2
MsgBox 'ok'
End Sub

Option Explicit
Public Type STARTUPINFO
cb As Long
lpReserved As String
lpDesktop As String
lpTitle As String
dwX As Long
dwY As Long
dwXSize As Long
dwYSize As Long
dwXCountChars As Long
dwYCountChars As Long
dwFillAttribute As Long
dwFlags As Long
wShowWindow As Integer
cbReserved2 As Integer
lpReserved2 As Long
hStdInput As Long
hStdOutput As Long
hStdError As Long
End Type
 
Public Type PROCESS_INFORMATION
hProcess As Long
hThread As Long
dwProcessID As Long
dwThreadID As Long
End Type
 
Public Declare Function WaitForSingleObject Lib 'kernel32' (ByVal hProcess As Long, ByVal dwMilliseconds As Long) As Long
Public Declare Function InputIdle Lib 'user32' Alias 'WaitForInputIdle' (ByVal hProcess As Long, ByVal dwMilliseconds As Long) As Long
Public Declare Function CreateProcessA Lib 'kernel32' (ByVal lpApplicationName As Long, ByVal lpCommandLine As String, ByVal lpProcessAttributes As Long, ByVal lpThreadAttributes As Long, ByVal bInheritHandles As Long, ByVal dwCreationFlags As Long, ByVal lpEnvironment As Long, ByVal lpCurrentDirectory As Long, lpStartupInfo As STARTUPINFO, lpProcessInformation As PROCESS_INFORMATION) As Long
Public Declare Function GetExitCodeProcess Lib 'kernel32' (ByVal hProcess As Long, lpExitCode As Long) As Long
Public Declare Function CloseHandle Lib 'kernel32' (ByVal hObject As Long) As Long
 
Public Const NORMAL_PRIORITY_CLASS As Long = &H20&
Public Const INFINITE As Long = -1&
 
Public Const STATUS_WAIT_0 As Long = &H0
Public Const STATUS_ABANDONED_WAIT_0 As Long = &H80
Public Const STATUS_USER_APC As Long = &HC0
Public Const STATUS_TIMEOUT As Long = &H102
Public Const STATUS_PENDING As Long = &H103
 
Public Const WAIT_FAILED As Long = &HFFFFFFFF
Public Const WAIT_OBJECT_0 As Long = STATUS_WAIT_0
Public Const WAIT_TIMEOUT As Long = STATUS_TIMEOUT
 
Public Const WAIT_ABANDONED As Long = STATUS_ABANDONED_WAIT_0
Public Const WAIT_ABANDONED_0 As Long = STATUS_ABANDONED_WAIT_0
 
Public Const WAIT_IO_COMPLETION As Long = STATUS_USER_APC
Public Const STILL_ACTIVE As Long = STATUS_PENDING
 
Public Const PROCESS_QUERY_INFORMATION As Long = &H400
Public Const STANDARD_RIGHTS_REQUIRED As Long = &HF0000
 
Public Function myShell(CommandLine As String, Optional Timeout As Long, Optional WaitForInputIdle As Boolean) As Boolean
Dim proc As PROCESS_INFORMATION
Dim Start As STARTUPINFO
Dim i As Integer
Dim ret As Long
Dim nMilliseconds As Long
nMilliseconds = INFINITE
Start.dwFlags = 1
CreateProcessA 0&, CommandLine, 0&, 0&, 1&, NORMAL_PRIORITY_CLASS, 0&, 0&, Start, proc
ret = WaitForSingleObject(proc.hProcess, nMilliseconds)
CloseHandle proc.hProcess
myShell = (ret = WAIT_OBJECT_0)
End Function

myShell ('rar.exe u <что> <куда>')