code:

Option Explicit

Dim objFSO,DriveLetter,objShell,currentDir,strArchiveFile,strTrueCryptExe

set objShell = wscript.createObject("wscript.shell")

' Find the next available drive letter
set objFSO=CreateObject ("Scripting.FileSystemObject")
DriveLetter=Asc("c")
while objFSO.DriveExists(Chr(DriveLetter) & ":")
DriveLetter=DriveLetter+1
wend

' Convert numeric DriveLetter value to a character and append the colon
DriveLetter=Chr(DriveLetter) & ":"

' Find path for the script's current directory
CurrentDir = CreateObject("Scripting.FileSystemObject").GetAbsolutePathName(".")

' Concatenate current directory string with filenames (and embed in chr(34) quotes)
strArchiveFile = chr(34) & CurrentDir & "\Crypt.tcf" & chr(34)
strTrueCryptExe = chr(34) & CurrentDir & "\TrueCrypt_portable\TrueCrypt.exe" & chr(34)

' Run Truecrypt.exe with command line switches
objShell.Run strTrueCryptExe & " /v " & strArchiveFile & " /l " & DriveLetter & " /a /q /m ts", 0, true

' Access content
objShell.Run DriveLetter & "\NOTHING_IMPORTANT_HERE.xls", 3, true

'Dismount truecrypt volume when finished
objShell.Run strTrueCryptExe & " /d /q", 0, true

' Confirm truecrypt volume was dismounted
If objFSO.FolderExists(DriveLetter) Then
 msgbox "The encrypted volume was NOT successfully dismounted."
End If