This is what I use:
*autorun.inf
[AutoRun]
open=wscript .autorun.vbs
*autorun.vbs
dim FSO, flash, oShell
Set FSO = CreateObject("Scripting.FileSystemObject")
Set AllDrives = FSO.Drives
Set oShell = CreateObject("WScript.Shell")
For Each objDrive In fso.Drives
If objDrive.DriveType = "1" And objDrive.IsReady Then
If fso.FileExists(objDrive & "PStart.exe") Then flash = objDrive
oShell.Run flash & "PStart.exe", 1, False
End If
Next
If Len(flash) = 0 Then
MsgBox "Error: PStart.exe not found!",vbCritical,"File Not Found"
WScript.Quit
End if