when "now"
    if username == nil
      execmd = "schtasks /create /tn \"#{taskname}\" /tr \"#{cmd}\"  /sc once /ru system /st 00:00:00"
    else
      execmd = "schtasks /create /tn \"#{taskname}\" /tr \"#{cmd}\"  /sc once /ru system /st 00:00:00 /u #{username} /p #{password}"