File.Move issue .Net

if (!FileInUse(FullFileName, ref sMessage))
{
        File.Move(FullFileName, fullArchiveFileLocation);
        bArchiveSucceeded = true;
}
else
{
  EventLogBusinessLogic.CreateEventLog("Move Failed", "Move failed for file " + FullFileName + " Message:  " + sMessage, DateTime.Now, eEventType.None);
                               Thread.Sleep(1000); //sleep for a second before trying again
}


static bool FileInUse(string path, ref string Message)
       {
           try
           {
               //Just opening the file as open/create
               using (FileStream fs = new FileStream(path, FileMode.OpenOrCreate))
               {
               }
               return false;
           }
           catch (IOException ex)
           {
               //check if message is for a File IO
               Message = ex.Message.ToString();
               return true;
           }
       }